First posted 21 January 2005. Questions of consciousness. Questions of the role of subjectivity. Questions of time. Questions of a Platonic reality. All still central to what keeps my curious mind busy... Penrose was the adviser of another of my scientific heroes: Julian Barbour.
Roger Penrose, the Oxford Physicist, is not convinced: quantum theory, he believes, is incomplete. In The Road to Reality he argues that a further revolution is required in quantum mechanics, as indicated by its inability to address the reduction process for the wave function (and thereby its inability to 'join up' with classical physics) as well as troubling incompatibilities with general relativity.
The time asymmetry associated with the wave function reduction (or collapse) upon measurement of a quantum system contrasts sharply with the symmetry associated with the propagation of the wave function itself. The latter can be made sense of moving either backwards or forwards in time; the former works only moving forward.
A more familiar time asymmetry, the one we experience every minute of every day, is grounded in the extraordinary nature of the Big Bang itself - its strikingly low entropy. The Big Bang was so ordered that the ever-decreasing order of the universe is a probabilistic near-certainty. This is what lies behind the 2nd law of thermodynamics and the 'arrow of time'. It points to the peculiar behaviour of gravity at cosmological singularities - not only the Big Bang but (less spectacularly) black holes.
The presence of this time asymmetry in both the reduction of the wave function and in the Big Bang suggests that gravity might play an important role in wave function reduction. Discovering this role would amount to a revolution that could well resolve the 'measurement paradox' and render quantum mechanics consistent with general relativity and contiguous with classical physics.
According to this idea, it is the gravitational effects of the classical measuring apparatus (and other macroscopic entities in our everyday world) rather than the perceptions of any observer that bring about the collapse of the wave function. As such, the reduction is an objective rather than a subjective one. This takes the conscious observer from the limelight of quantum theory. How does this happen? As the wave function propagates through time, non-uniformities develop in the distribution of energy and matter among its superposed states, and at some point become gravitationally significant. The gravitational interaction with the measuring apparatus (or other macroscopic entity) then brings a collapse into a measurable single state.
Although Penrose takes the consciousness out of quantum reduction, in The Emperor's New Mind he puts quantum reduction centre stage in consciousness, thereby turning the world (as seen by conventional quantum theory) on its head. These same quantum gravitational effects account for the difference between consciousness and artificial (computer) 'intelligence', and Penrose calls upon them in his rejection of the computational theory of mind. There are things - including non-algorithmic, non-computable ones - that the human mind can comprehend while no computer (Turing machine) possibly could. This is in keeping with Godel's theorem, which states that no formal mathematical system (or at least none of the richness required to handle even common arithmetic) can be complete. There must always be truths that cannot be expressed without recourse to 'meta-mathematical' language that is not part of the formal system.
Penrose suggests that our access to such truths is due to quantum fluctuations, gravitationally induced, within the brain (he suggests maybe in the microtubules of the neurons' cytoskeletans). Multiple states may exist in superposition in our brains until gravity triggers a collapse to a specific state, with resulting (possibly non-local) effects on our neural states. This is something that is not possible (at least for now) with computers.
There is a deep connection among the time-asymmetry of the wave function reduction, the behaviour of gravity at singularities and the presence of non-algorithmic (non-computable) elements - including consciousness - in the world. This helps to explain the relationship among Penrose's "Three Mysteries":
There is also an "Escher element" to the relationships among the three mysteries. Escher was an artist (and obviously a mathematician) whose works included paradoxical staircases and streams that seemed to always lead in one direction (up or down) yet returned to their own source.
In Penrose's three world / three mystery model, a small portion of the mental world is all that is needed to capture the mathematical one (since we obviously spend lots of time considering other things). Similarly, a small portion of the mathematical world is applied to the collected (total) formalism of physics, with much else being dedicated to other questions. And finally, only a small portion of the physical world (that part that makes up our cells) is drawn on to explain the mental one. Each part is able to 'swallow' its neighbour in an illogical, unending cycle.
Penrose believes that the secret to this mystery of the mysteries is that all these worlds are in fact one. Perhaps in a holographic, holistic, non-local sense like that evoked by David Bohm, another of my creative scientific heroes?
First posted 15 April 2006. These days, I tend to think of the brain a lot less when I'm thinking of the mind, but my sense of wonder for whatever it is that is behind our mental experience is undiminished.
Michael O'Shea's The Brain: A Very Short Introduction has shown me that my longstanding wonder with the brain has been understated. You see, I have marvelled at the complexity inherent in a collection of 100 billion neurons - each with a thousand synapses, connections with other neurons - and the effectively uncountable number of possible brain states implied by the permutations of these on-off switches.
O'Shea is also impressed by this, but he adds several other elements of our current understanding that demonstrate that the metaphor of a network of binary electrical switches is far too simple:
All of this suggests that the challenges of 'porting' human intelligence to computer hardware ( a la Ray Kurtzweil) are vastly greater than I had thought. The challenges are similarly greater for efforts such as Dan Lloyd's to eventually map mental states to brain states: the state space, already mind-bogglingly large, is vastly larger still.
It even makes me slightly more sceptical about Julian Barbour's timeless theory of time, because the asynchronous nature of the brain's neuronal (and glial?) interactions doesn't seem to fit well with the notion that particular brain states are but tiny subsets of instantaneous universe states (or Nows) that happily happen to contain records that act as bridges to other Nows. How instantaneous is a Now? If mental states are tied not to instantaneous brain states but are affected by the frequency of repeated neuronal firing, then can a mental state reside within a single Now, given that such a Now, by definition, can contain no change (i.e. no repeated firing)?
But there is a way out. I guess if the brain encodes in each instant information about its state in previous instants (as in discussion of the specious now in Dan Lloyd), then there is no necessary inconsistency between the unquestionable existence of subjective experience and Barbour's theory of time.
First posted 28 June 2006. My view of time and consciousness is surprisingly close in this 11-year old post to what it is today, even though I had not been exposed at that time to the main elements that now underpin my reasoning.
Several pairs of unreconciled truths (as in best operating guesses) interest me deeply: Quantum mechanics & General relativity, Determinism & Free Will, Materialism & Consciousness. These pairs are not unrelated, could indeed be different manifestations of the same chasm. The paradox that may interest me most of all captures aspects of all three and is almost certainly inextricably entwined with each, and that is: Space-time & Temporal becoming.
The paradox has two elements. The first, in a nutshell, is that our best understanding of space-time tells us that it is a complete, unchanging, four-dimensional (perhaps with seven further dimensions wrapped tightly around themselves, unextended) whole, but our direct experience is of a temporal flow with each moment different from the last. All is constant, yet the only constant is change itself.
The second is that while space-time itself has no privileged set of parallel planes that can be called Nows (each inertial frame parses out space and time in a different way, with the Nows as planes at different angles to one another) , we each indisputably experience a clear distinction among past, present and future. The flow from the latter to the former hearkens back to the first element of the paradox.
In an interesting paper, entitled "The Physics of 'Now'", James Hartle takes us some of the way towards a reconciliation.
Space-time is a four-dimensional grid, with each point being an event. If we label one axis as the the speed of light multiplied by time and the others as the space dimensions, then one can imagine two cones, extending in opposite directions parallel to the 'time' axis and meeting at a designated point, or event. The one pointing back toward the Big Bang is the past light cone for that event, and the one opposite it is the event's future light cone.
There is a reason these are called light cones: given the chosen units of the time axis and the fact that nothing can travel at speeds exceeding the speed of light, all points (events) within the 'backward' light cone can be said to be in the given event's past, they could have played some part in the evolution that led to the given event's occurring. Similarly, all points in the future light cone can possibly be affected by this given event. Points outside these cones cannot be said to be in the given event's past or future. They are what is called 'space-like' separated from it.
If we imagine that event or point as being one of many that make up the history, or world line, for a person as that person travels through life (and space and time!), then, within that person's frame of reference, the plane that runs through that event and is perpendicular to the time axis might be defined as a Now or instant for that person.
But the thing is that that person's frame of reference is not privileged, is nothing special. So although it might be called a Now for him, it is not a Now for the universe. Other people could be travelling at very great speeds relative to him, and their Nows would be askew with respect to his.
As it happens, all we humans exist very close to one another (on a cosmological scale), and we move only at very low velocities relative to one another (as compared to the speed of light). So our Nows are for all intents and purposes not only parallel but even simultaneous. Still, this is just a local accident.
Why do we distill the time dimension from the space ones and experience it as a flow from future to past? Hartle believes it is a function of the way that we collect and process information. Placing humans within a broader set of entities he calls Information Gathering and Utilising Systems (IGUSes), he models a simple IGUS to demonstrate his thinking.
In essence, we have 'registers' for current input and for memories of past input. These registers contribute directly to conscious thought both directly and indirectly, the latter through subconscious updating of our 'schema' or underlying operational models for dealing with the world around us.
In any moment, or more to the point, at any event along our world-lines, the 'current input' register is populated by what we are experiencing, the remaining registers are populated by what we experienced in each of several immediately preceding moments. The direct 'feed' from the 'current input' register to conscious thought gives the sense of Now. The fact that any brain state enfolds information from previous brain states ( in the other registers), gives a sense of both a past and of a flow to time. The future is not represented in any register but is rather the object of calculation in both conscious and subconscious processing.
But why does this flow move in one direction rather than the other, or rather than in both? Hartle appeals to two old dears of physics, the 2nd law of thermodynamics (which states that entropy must always increase), and the nature of electromagnetic radiation. I've talked about the first elsewhere. The second is worth mentioning a bit more about. Anything we see has radiated from some source. Electromagnetic radiation only ever travels in that one 'direction' - from source outwards.
In a sense, then, the past can simply be defined as the direction in time from when radiation strikes our retina to when it is (was) emitted. Information only travels that way. Since gathering and processing information is what we do, we naturally take on or assign this direction a prominent place, simply through our interactions with the world.
As ever, I'm sure that I've been less than perfectly true to Hartle's original argument, so do read his paper.
I will say, though, that I think he leaves two questions unanswered. They may well fall outside the scope of his work, but they are related and interesting. First, Hartle mentions repeatedly that we EVOLVED into the IGUSes we are, to process information as we do, because that is what worked. He is doing nothing more than making one specific reference to the accepted truth of Darwin's thesis. But when one thinks of space-time as a four-dimensional, unchanging and complete totality (as I believe it is), one can't help but think differently about evolution.
We no longer say, things are this way because they evolved to be so, and they evolved to be so because being so conveyed survival and reproductive benefits. That is all true WITHIN the time dimension, but within the eternal space-time picture, that we are this way is just that we are this way. Both our present state of evolution and every other step in its past and future exist eternally. So one then asks, why is THAT so? Why is it that this relationship within four-dimensional space-time exists? I don't have an answer. It is just SO.
Second, it is simple enough to refer to a given event on my world-line, look into the 'current input' register and say, "That is my Now". But the interesting point is that EVERY ONE of the points on the 'conscious' segment of my world line is a conscious now, and every one exists eternally, side-by-side, as it were, in space-time. Why do I not experience them all at once. Why do I only experience THIS one and now THIS one?
I do have my own answer to this question, and it is that we ARE experiencing ALL of our Nows eternally, although somehow only ever in one channel at a time. Every instance from our first sentient experience through to our last is experienced by us eternally. Each exists at some event in space-time, but all are there in the eternal 4-D block that is existence. So we don't get life-after-death as such (because the 'after' shows that we are talking within the time dimension with that phrase), but we do get eternal life! And that eternal life is no better or worse than each instant that you live. Moments of suffering are eternal, as are moments of elation, despair and euphoria. Drink deep. Live it up!
First posted 17 Feb 2004 - This film covered a lot of ground. It may have lacked rigour. It may have made insinuations that outreached any fact base. But you can't deny it prompted questions and presented interesting material in relatively digestible form. My own views have shifted significantly from those I held at the time of this review. Some are now closer to the film's, some still not.
Having seen 'I Heart Huckabees' on Sunday, I saw a preview screening of 'What the Bleep Do We Know' this evening - quite a philosophical week. 'Bleep' will probably launch properly in London in March or April.
Well, Bleep certainly covers a lot of ground. I am on board with the need for a paradigm shift - from one dominated by the residue of our longstanding and recently ended infatuation with major western religions to something that retains the connection with the numinous while using what modern science has to offer.
I have to say that the paradigm I envisage differs in a fundamental way from that suggested by the film, but it also shares much ground. Irrespective of whether I or anyone else actually subscribes to the film's specific direction, it is a must see - simply because it is so thought-provoking.
Particular items that caught my attention or stirred a reaction were:
Quantum mechanics (QM)
The film starts with a strong version of the Copenhagen Interpretation of QM, which says that sub-atomic particles cannot be said to exist independent of observation. Unobserved, 'they' exist only as potentials, the probabilistic evolution of which is well defined by a mathematical construct called a wave function. In this wave form, the 'particle' exists as a weighted superposition of all its possible selves (with different positions and momentums for each potential self). Only upon measurement by an observer does the wave function 'collapse' to a unique particle with definite characteristics (not all of which can be known to arbitrary accuracy at the same time). This interpretation obviously gives a special role to the 'observer' in nature.
This is combined with a specific view of the self, one in which Mind stands outside the laws of material nature and in a position of primacy relative to the material world - literally Mind over Matter. I guess you could say the film was espousing an Idealist as opposed to a Realist (read materialist) view of the world: thoughts, ideas, intentions and emotions are the primary building blocks of the world, not atoms, molecules and cells.
The film intertwines these two propositions and draws the conclusion that we each create reality everyday. Further, by adopting more positive attitudes and engaging in more positive thought patterns, we can impact the material world around us to make our world a better place.
As you'll know if you've read my articles on QM (If you think you understand this, then you don't, Quantum Determinacy, Problems with Quantum Orthodoxy, and Revisiting the Quantum - information please) and the Self (Who Am I?, Destiny, Subjective Objects), I disagree fundamentally with each of the two propositions above. I am a causal realist at heart, believing that there is an objective material world that exists independent of us and that subsumes us. And although I think that the Mind is awe-inspiring, I think that it is wholly resident in and reliant on the body.
So without going into any refutations of the film's positions (because I've discussed that in the articles I've mentioned), I'll just say that the film's position on those dimensions does not resonate with me. I don't view either of them as absurd in their own right. However, I do think that the leap to the overall conclusion about our ability to literally impact matter and space with our minds is a bit far. QM's interpretation is still a mystery, with many holding views close to the interpretation cited in the film and some holding views closer to mine. Consciousness is also a puzzle, with clear-thinking people on each side of the Idealist - Realist debate. However, just because QM and consciousness are both unexplained doesn't mean that they are related to one another in any way, let alone a causal tie as blunt and direct as the film proposes.
The Arrow of Time
One of the contributors pointed out the peculiar asymmetry of time. Most (I don't know whether we call say 'all') of the mathematical formulae that so accurately describe the world around us are indifferent to the direction of time, working just as well backwards as forward. Yet we can only experience time in one direction. We can (if we can trust our memories) have knowledge of the past but not of the future. We are troubled by the thought of our not living into the unending future, but we have no problem with the fact that we were not alive for the many thousands of years before our birth.
Some (but not this contributor) have suggested that time's arrow is tied to the second law of thermodynamics, which says that in a closed system, entropy increases over time. Entropy MUST increase as time moves forward, so perhaps this irreversibility drives the same irreversibility in time. But upon closer inspection, entropy's increase is not absolutely necessary: it is only probabilistic. It just so happens that the universe began in a relatively ordered state. Since there are many more (uncountably so) disordered states than there are ordered ones, entropy's march is staggeringly probable - NEARLY assured. Yet that is not the same as being necessary, absolute. So... if we are to tie time to entropy, we would also have to accept that time's direction is not irreversible in theory, but is only practically guaranteed by the high probabilities discussed above.
The Brain and learning, habituation and addiction
Several contributors discussed the role of neural pathways or networks in our behaviour. We reinforce the formation of certain sets of connections through our habits. The reinforced sets 'wire' themselves to respond to the frequent call for their combined performance. Other possible combinations, if not called upon, do not wire themselves up. We can, through conscious habituation, re-wire some of these networks (e.g. the ones associated with more positive outlooks, more pleasant moods, more confident postures and more successful behaviours).
And this electrical component is accompanied by a chemical one, with parts of the brain creating (or causing to be created) different chemicals for different needs. Just like we can become addicted to external drugs, we can become addicted to some of these internal, home-made concoctions. We then engage in the behaviours and nurture the states of mind that give us our fix.
The important point is that a bit of us can stand outside the fray, perhaps up on the mental balcony, observing and intervening to break the vicious cycle. But we have to recognise and support that bit, exercise it and have confidence in it.
I don't know the science well enough to comment on the accuracy of this 'folk' version of it, but it doesn't seem outlandish; in fact, it jibes quite well with the rough understanding I have from some previous reading.
I'll see it when I believe it
One scene is built around the story that the natives in the Caribbean did not see Columbus's ships as they sailed in, because they had no visual or mental construct for a ship. The more general point is that we cannot see or accept things that do not already exist in our mental model or paradigm.
To be honest, I don't buy the foundational story at all. I can accept that the natives would not know that the ships WERE ships. I can understand that they would be confused as to what these dark patches on the horizon were, confused by the shapes they became as they grew closer. But I cannot believe that they literally did not SEE them.
Like everything else in the film, though, it is thought provoking. It recalls to mind a vague picture I have of how we deal with sensory input and with anomalies in particular. We are bombarded with sensory input, with much more than we can process, in every waking moment. Our brains are partially hard-wired through evolution (i.e. natural selection) to help discern the useful info from the 'white noise', and our particular experiences further shape the more plastic aspects of that filter.
From our earliest days, we begin to assemble our working model of the world. What matters? What does not? What framework allows us to maintain internal consistency across the broadest range of our experience - to make sense of the world? When new input arrives that is labeled as irrelevant, we do not attend to it (unless perhaps we pay the price for ignoring it and our brains pick up on that fact and adjust the framework). When new input fits the paradigm and is labeled as important, we attend to it.
But what happens if new information is so far outside our accumulated experience and reasonable extrapolation from it that we can make no sense of it at all? We tuck it away into a certain bit of the brain where it sits in a cache; at night, while we sleep and dream, among the routine brain maintenance that takes place is a re-assessment of the framework (or paradigm) in the light of any new anomalous information. What is the smallest adjustment that can be made to the overall model in order to accommodate, make sense of, this new input? Do we need to scrap the whole model and start anew (when rocks begin to talk or we find out that we are just carnival entertainment for some other, alien and invisible race!)? If the accommodation necessary is too large, we may well end up just disregarding the anomaly (the Red Sox didn't REALLY win the World Series) and just continue with the paradigm intact.
So you can see that I identify more than a grain of truth in the film's underlying point here.
Back to the addiction theme, another segment looked at it from the somatic cell perspective. Every cell has loads of receptors for receiving information from its environment, including the chemical drinks discussed above. If the receptors are incessantly bombarded by some protein 'hit' they shrink and become less responsive to it, meaning it takes more of it to give the same 'fix'. Cells can then become so engrossed in getting their next 'high' that they neglect other important functions like communication with neighbouring cells and even elimination of their own waste products. Keep in mind that I'm talking about 'internal', not 'external' drugs here (although I wouldn't be surprised if the story were much the same for external ones).
You can tell by my over-use of analogy that I'm not up to speed with the proper science here, so I can't judge the accuracy of the scientific claims. It does, though, appeal to common sense. (Yeah, yeah, I know, common sense often leads us astray when we venture away from the normal life scales and conditions in which it developed.)
One contributor spoke (a bit too loosely, I think) about cells being not only alive - an assertion with which I wholly agree - but also conscious. She said a cell was conscious because it interacted with its environment and processed chemical information. This doesn't, for me, suggest consciousness. Or, to put it another way, if it DID qualify as consciousness, then we would have to admit that computers and computer networks are conscious. Perhaps we should...
No good, no bad
Several contributors pointed out that there is no objective good or bad 'out there' in the world. A belief with which I am in agreement, as you can read in my articles: Right and Wrong, Sources of Morality, Ethical Notes, Disobedience, Pragmatic Ethics and Nietzsche's Call to Creativity.
No Personal God
All contributors who discussed religion found the creation of a person-like personal God harmful to mankind and in many instances antithetical to what they saw spirituality as.
I tend to agree that, however powerful, insightful and well-intended the original spiritual messages are, when organised religion accretes around them, the foibles of man dilute, pollute and hijack them.
This isn't at all to say that all clergy are guilty or that all followers are silly. I just think that the more organised a belief structure is, the more likely it is to lose sight of the wood for the trees.
As I said, there were a number of things with which I agreed and a number of things - including the major thesis - with which I didn't. Still I can heartily recommend 'What the Bleep Do We Know' as an interesting, challenging, thought-provoking film that may well make you want to sit down and put your thoughts to paper.
First posted 12 Apr 2004. Tying together Robert Pirsig, Eckhart Tolle and Nietzsche - early influencers of how I now see the world, this post also touches on music, one of the great loves of my life. Just a taster. Oh, and I got rid of my Vespa a few years ago, so now the maintenance analogies have to find their home in the bicycle world...
Ever find yourself in the middle of a confrontational daydream - hypothesising things that might go wrong in the future and then spinning through in your head how you might deal with them? Or have you caught yourself re-living an event (whether glorious or humiliating) from the past, perhaps second-guessing your actions? Or how about sitting in traffic, in a queue or in a boring meeting at work, waiting to be able to get on to something interesting or important that lies in the near future?
If you're like me, you probably spend a fair bit of time thinking about the past, the future or some alternative and preferable present. We do it so much that we think nothing of it. Yet when you really step back and consider it, as I do whenever I re-visit Eckhart Tolle's The Power of Now like I have in the past week, you realise that all this mental hyper-activity is really a useless exercise.
Let's acknowledge up front that of course it is useful to reflect on past events in so far as that reflection generates learning that better prepares us for the future. Likewise, it is certainly useful to think about the future so as to identify things you can do today and along the way to make that future better. Our brains are wonderful tools for learning from the past and planning for the future, and we should stroke them lovingly for the outstanding work they do for us on those dimensions.
The problem is that, at least for me, most of the time spent dwelling on the past or fretting about the future involves little of this useful activity. If learning and planning were all we did, we'd spend a small fraction of the 'non-Now' time we do. No, what we do is mull over things again and again, causing our hearts to race and inducing other fight-or-flight reactions in our bodies. We put ourselves through unnecessary worry, regret or other pain.
Although it is almost too obvious to warrant mentioning, let's just remind ourselves that there is NOTHING we can do about the past. Aside from some science fiction writers and Hollywood producers, no one has found a way to reverse time's arrow. It naturally follows that obsessing on the past (beyond the aforementioned reflection for learning's sake) is useless.
Not quite so obvious, but equally true, is the point that worrying about the future does nothing to avoid or mitigate negative future events. Once again, some planning might help, but beyond that, much of the future-anxiety we experience is driven by phantoms, dreamed up proto-scenarios that may or may not ever materialise.
The whole 'so-what' of this is that all we can ever directly influence is NOW. Every action we ever take is taken in the present. We might as well pay attention to the present, since that is all we ever directly experience.
So at one level, a strictly practical one, I personally am trying much harder to minimise the time I spend with useless, unhelpful and uncomfortable past- and future-oriented activity. Don't get me wrong: I do not purport to be a guru or an expert on this. I just struggle along like everyone else, but I AM doing better at simply recognising when I begin to drift into unhealthy past-or-future zone. And just recognising it really does go a long way toward making it stop.
As for the future (because I tend to be much worse about drifting in that direction than drifting toward the past), I find lists to be very helpful, and here's why. If I think of something I need to do in the near future and don't write it down, it just swirls around in my head until I get it done. And it doesn't swirl around peacefully, it leaves a trail of anxiety. Whereas if I write it down, then I feel it is captured. Then I just cross it off when I do it, whenever that is.
Now some people have problems with lists, because they make these really comprehensive ones that try to encapsulate EVERYTHING they need to do to 'get themselves together.' Having filled page upon page with these details, they then look at the list and are instantly overwhelmed by the magnitude of the project before them. All I can say to this is that we all need to prioritise and schedule among the demands on us. You work your way through that list the same way you eat an elephant - one bite at a time.
A Deeper Level
Now let me turn to a slightly different problem, that of following our minds into alternative, preferred presents rather than directly our minds towards the ACTUAL present in which we sit. This is the category of problem that includes the anxiety in traffic jams, long queues and other 'useless' periods.
At the risk of (once again) stating the obvious. Either we can do something about the situation in which we find ourselves or we can't. In the former case, we should just get on and DO it. In the latter, we can but make the most of it. In either case, the first step is to accept (which is not to say celebrate) the real present, recognise and acknowledge it. Only having done that can we figure out whether we can usefully act. All too often, I just skip this all-important step and move straight into emotional over-reaction, with the accompanying unhealthy physical manifestations of stress and frustration.
Now this is where I could really be a lot truer to my professed world-view. I believe that whatever happens is the best that CAN happen and the worst that CAN happen. In other words, whatever happens, happens NECESSARILY. By better keeping this in mind, I can more helpfully acknowledge what IS and then work WITH it to the limits of my ability.
There is another reason for paying more attention to and granting acknowledgment to the present moment. There is an entire world out there as well as within us. Our real contact with that world, is entirely in the present. If we restrict the attention we give to it by frittering away part of our capacity on past and future ghosts, then we degrade our connection with reality.
In Zen and the Art of Motorcycle Maintenance, Robert Pirsig speaks of quality - that characteristic that defines something that is good from something that is not. In essence, quality surfs right on the leading edge of the present moment. It imposes itself on us in its raw, undefined Romantic form in the instant between awareness and consciousness. Once our rational, Classical consciousness - a filter defined by our make-up and experiences - takes hold of it, we analyse it, dissect it and place it into the appropriate category or pigeon-hole. If our awareness is in itself inhibited because our minds are leading us away from the present to battle past or future demons, then we are twice poorer: first in gaining only an attenuated or partial experience and second in what we can extract from that experience.
The mechanics who screwed up Pirsig's bike weren't sufficiently engaged in their work to do a good job. This might have even been the case if they did care deeply about achieving a good final product. The point is that you have to care about what you are DOING, not what any future product of it is. Caring about what you're doing (which is always in the present moment) is the single most important thing in motorcycle maintenance - and of course by extension, the most important thing full stop.
For Nietzsche as well, reality was this pre-rational raw wave within an ever-evolving flux. The front edge of that wave is all we can ever access. In fact, this unmitigated experience is so powerful that we have evolved physically and socially so as to buffer ourselves against it. Given our self-imposed safety padding, designed to protect our sanity, the closest most of us can safely get to unadulterated Being is through music.
Music speaks to us without words, riding a standing wave at the edge of our awareness and the rest of existence, with which that awareness is inextricable entwined and essentially one. For Nietzsche, only a new being, born of man but incomparably braver and sturdier, can 'face the music' without being overwhelmed. It opens the window to not only the beauty but also the terror of existence.
Just to come back to the mortal world, I have to admit that my experience with music has never been this earth-shattering. Yet I do see something in what Nietzsche is saying. Music does help bring me into and hold me in the present moment. It brings my mind out of its self-generated battles and makes it still. Then, whatever I turn to do, I do with a clearer mind. I am able to immerse myself more deeply into that activity, in the DOING rather than the product.
I don't do my own maintenance on my 50cc Vespa, but if I did, I would want to have my MP3 player nearby.
First posted 24 Oct 2005. I used to be a 'the mind reduces to the brain' guy, whereas now, I'm more of a 'the brain (and everything else) reduces to the mind' guy. The book that this post refers to was my introduction to phenomenology - the study of experience. Thinking of the world in terms of experience has ended up being the biggest shift in how I see things. That shift has taken more than 10 years, from the time of the post below, though.
The Internal World
All we ever have direct access to is our mental states. Those states could be the result of our interaction, via our sense, with the external world; they could be part of a dream; they could come from wires and electrodes stimulating our brains, which sit in vats of syrupy liquid in a world run by computers. Both philosophy and science fiction have wrestled with questions of whether those mental states correspond to or represent an external world. The question is no less interesting (and no closer to being answered) than it has ever been.
But those mental states, that internal world itself, is rich ground for investigation as well. Phenomenology is the study of experience, and a recent book I read was my introduction to it. The book, an atypical mix of novel, philosophical introduction and scientific primer, is called Radiant Cool, and here is what I have taken from it:
I've always taken objectivity to mean the view 'from outside' and subjectivity to be the view 'from inside' a person. But, using a specific visual perception example, even in our internal 'views' we are aware of the difference between some relatively stable mental object, say the image of a chair, and any number of particular angles (or points of view) from which that chair can be seen.
Think about it. As we walk around a chair, looking at it, our mental states do not feel like we're seeing a constantly changing stream of things, but rather that there is a single thing there, which we are viewing from a constantly changing angle. All of this is equally true if we simply imagine walking around a chair, which shows that the physical presence of a material chair isn't necessary. The point, which had never occurred to me before, is that even within our subjective experiences, there is a stability and assumed objectivity of entities rather than just a constant flux. This is despite the fact that the sensory input we receive is literally nothing but an ever-flowing flux. So... there are non-sensory elements to our experiences, even to those experiences that - on the face of it - seem to be purely sensory.
Affordance / superposition
When we think about it a bit more, it becomes obvious that the in-built assumption or experience of objectivity / permanence is not the only non-sensory element to our perceptual consciousness. Everything we see presents itself not just in its bare form but always with a collection of non-sensory baggage - inseparable emotions, associations, anticipations, etc. This property of immediate perceptual objects to 'carry' these other properties has been called affordance or superposition.
The possible bits of baggage that can accompany perception are virtually innumerable. We can model a theoretical mental-state-space of consciousness, with each possibility constituting a binary (either experienced or not) dimension in that space. If each conscious moment were represented by a time 'slice' of this space, then putting them all back to front temporally would create a squiggly line tracking through state-space moment by moment.
In fact, the most important of these non-sensory elements - perhaps even THE defining one for explaining consciousness - is temporality itself. Our mental worlds are built upon it. And I'm not speaking here of memory and anticipation - casting back or forward from the present moment. Temporality is embedded even WITHIN each moment. Each immediate experience can be thought of as having three components: retention, presence and protention. The middle one is the instantaneous snapshot of the flux of sensory input. Retention is the context in which that snapshot sits, grounded in what the previous instant contained. Protention is the immediate projection or extrapolation of what the retained and present elements imply for the next moment.
A simple but insightful example brought this home to me. Think of a musical melody. In any instant, the only SENSORY element of the experience is a single note, yet your experience of that note is inseparable from the pitch, volume, duration and other qualities of the notes immediately before and after it.
Lloyd used diagrams and explanations of simple, synchronous neural networks to show how temporality can be embedded within a cognitive system. If some of the nodes (neurons) in the system encode the previous values of the neurons that receive and 'process' the sensory inputs, and if those time-lagged neurons feed back into the sensory processing ones, the feedback loop ensures that each instant recursively captures all previous instants. Then the 'output' from the sensory-processing neurons constitutes the system's best guess for what the next moment (immediate future) will be. A number of examples showed that this model world works very well at keeping time and tracking the future. But do brains work this way?
Lloyd then moved from toy brains to real ones, using the tools currently at science's disposal to look at the evolution of brain states over time while subjects performed different mental tasks. The results suggested that we can track these states quite well, and Lloyd showed how further empirical testing can pull much of the discussion from the world of the philosopher to that of the scientist. But it was also obvious that further technological advance was necessary to make findings more exact and more robust.
Mental state = Brain state?
Where is this all going? Well, Lloyd and others think that the ideal objective is a deepening of our understanding of both brain states and mental states, an understanding that may well include a one-for-one matching between the two that reduces the mental to the physical, firmly placing the mental world within the natural world. I say 'ideal' objective because we may never be able to reach a neuron-by-neuron level mapping of brain states. If that degree of specificity is required for perfect mental state matching, then we may be stuck with some degree of averaging and clumping of brain and experience states. Still, this could provide the empirical basis for finally dumping Cartesian dualism, the Cartesian theatre, and all the misunderstanding they create.
Originally posted 29 Nov 2003. Back then, I took away some interesting practical points and identified some common ground. I didn't accept the metaphysics. I didn't really get the metaphysics. I sort of do get them now. Although the nature of metaphysics is that we can never know whether they are right (hence the meta), these days Tolle's picture is one that makes intuitive sense to me and is not inconsistent with any evidence.
Eckhart Tolle's The Power of Now - A Guide to Spiritual Enlightenment signposts a journey toward inner peace. I took much from it when I read it a year or so ago. I don't happen to agree with Tolle's metaphysics (time is an illusion, the role of the unmanifested), but I think he makes some good points.
I am no interpreter of Tolle's work, so I do not seek to set forth his argument here. Instead, I would like to highlight a number of the parallels and tangencies between his points and the way I think about Being, Life, Sentience and Consciousness and about the relation between the objective and subjective perspectives.
Tolle believes that we let our rational, conscious mind get in the way of real life. It is a useful tool, but we let it run out of control. How does this manifest itself? We spend too much of our lives planning and fretting about the future or reliving and regretting the past. Our memory and our capacity to form intentions and plan their execution keep us from opening to the raw experiences of life's moment - the here and now.
Tolle goes on to say that there is actually nothing else but the Now. I disagree with this, instead seeing time as one dimension of space-time, just as real as the others, but different from them. Whereas we can move freely among the three spatial dimensions, we are dictated to by the time dimension. We have to move at its speed.
Our access to that dimension is only through the narrow slit that at any moment is now. Our memory gives us imperfect access to the past, as if looking through a rear-view mirror. Our scientific understanding allow a very limited and narrow predictive look at the future. But we can only ever experience now - this moment. This differs hugely from what an objective observer, sitting outside space-time (a-la Flatland fashion) would see. He would see the stretch of all time just as easily as he sees the extension of space. To use a film analogy, he would see the whole reel unwound at once, rather than be restricted (like us) to seeing one frame at a time in quick succession.
Metaphysics aside, I think that Tolle makes a good practical point. If we let our self-conscious powers run amok, dwelling on the past, reliving it, resenting it; scheming about the future, preparing for every eventuality, plotting moves, then we lose out on the wonders that our senses are trying to present to our (animal) sentient awareness. In over-exercising that which sets us apart from other animals (perhaps in the vain hope of convincing ourselves that we're not animals) we miss the simple pleasures of qualia - warmth, melody, beauty. Our unique subjective worlds become cluttered with 'noise'.
Tolle also emphasises that we are not our minds. For him, each person has an eternal presence, an essence part of yet identical with the great unmanifested. I agree that we are more than our minds, though I see it differently from him. Rather than appeal to a supernatural 'unmanifested', I find a foundation in the natural world - the stuff of which we are made, the recipe by which we are made, the chain of actions of which we play a part - basically the eternal web, or flux, of everything. Our roots reach endlessly to the past and our legacy stretches ceaselessly into the future - two opposing cones with us at their common meeting point.
Anyway, to re-iterate the common ground, don't confuse your self with your mind, especially your self-conscious, rational mind. It is a special, important part of you, but it is rooted in more fundamental stuff.
First posted 15 January 2006. Barbour's picture is about as close to my worldview as you can get from a materialist perspective. I 'just' replace his infinite set of particle configurations with an infinite set of experiential moments.
I've just read Julian Barbour's The End of Time, a good history of the physics and philosophy of time that also puts forward a radical view of time itself.
Update to the Block View
Barbour's historical account helped me to realise that the view of time I put forward in All the Time in the World (or more specifically a couple of aspects of it) is Newtonian and doesn't recognise a couple of truths from the relativity revolution.
In that post I said, when distinguishing between the space dimensions and the time dimension in space time that although we can easily imagine orienting a three-axis grid however we like in space, we cannot think of 'rotating' the time axis at some angle. In fact, special relativity and Minkowski space-time do away with absolute simultaneity and DO in fact allow rotating the time axis in 'trade-offs' with the space ones. (It also gives us light cones and time-like, space-like and light-like relationships among events, but I'll save that for another post.)
General relativity goes even further by getting rid of the idea of 'clean' Euclidean planes of simultaneity altogether, at least in the vicinity of mass and the distorting effect it has on space-time. Although I think I've got my head around the special relativistic implications for my view, I can't quite claim to be on top of what adjustments general relativity requires.
Getting rid of the vessel and defining a new space
Barbour doesn't adopt the 'block view' of time that appeals to me. Instead he asserts that time does not exist. Einstein's radical step was to dismiss the notion of absolute simultaneity and to take the very practical approach of asking what we could know via the use of rods and clocks. Barbour thinks a further radical step is necessary, and his denies not only the existence of temporal becoming, which is denied by many others, but also the existence of any space-time 'vessel' for holding all the things that exist. In the absence of that vessel, all that matters is the relative positions of the things themselves. A scientist named Mach, whose influence on Einstein was great but fell away in Einstein's final analysis, is the father of this view.
Barbour believes that a Machian world is strongly suggested by Einstein's general relativity, but that Einstein didn't quite carry things through far enough to see it. He goes further to say that such a view may be exactly what is necessary to reach an acceptable theory of quantum gravity, reconciling and uniting Einstein's cosmological theory with the weird microscopic world of quantum dynamics.
For Barbour the building blocks of reality are the infinite possible relative positional configurations of existing particles. Each of these configurations might be thought of as an 'instant'. (Certainly, in a layman's evolutionary view of time, each instant corresponds to some configuration of particles - a snapshot of the universe, although one might ask just how long an instant is.) These snapshots are not layered neatly onto one another to create a book or block. They are just in a jumble, like wooden shapes in a bag. So Barbour's view might be called the 'timeless bag' view.
Now if we can imagine a mathematical space of huge (indeed, infinite) dimensionality, we could match each possible configuration of the universe to one point in that space. Barbour calls this space Platonia, and it is central to his story.
The case for Structuralism
The term structuralism, as applied here, is mine, not Barbour's. His theory is structural in that the 'shape' of configuration space (Platonia) determines how the wave function - that messy thing (or mathematical construct, depending on your view) central to quantum mechanics - hovers over it, making some configurations more likely than others. So causality exists not 'vertically' (i.e. through time) but rather horizontally (i.e. sheerly through eternal relations and resonances).
Barbour reminds us that Schrodinger's first derivation of his wave equations was actually a time-independent one. It predicted with great accuracy the energy levels in the Bohr model of the atom. Schrodinger went on to develop time-dependent equations, which came to be viewed as the more fundamental relations. For Barbour, the first is the more fundamental, and it is strong support for a timeless universe.
He also cites what is known as the Wheeler-DeWitt equation. This equation is controversial in that its derivation may be flawed, in that it is mathematically incomplete (new techniques must be developed to solve it), and in that its interpretation is not clear. But Barbour thinks it could be an early version of the ONE equation that describes the whole universe, uniting the two great theories of relativity and the quantum. And he thinks that it points to the 'timeless bag' view.
Philosophically, Barbour's interpretation of quantum mechanics has much in common with Everett's Many Worlds interpretation, in that it gives positive ontological status to all possible configurations of the universe. But whereas Everett thought in terms of infinitely branching histories, all of which are 'real', Barbour sees, no 'real' histories, since histories require time, the existence of which he denies. No, the infinite possibilities are simply configurations - those wooden shapes loose in the bag, those individual points in Platonia. Every possible configuration exists, and the quantum wave function for the universe determines the 'number of copies' of each (which is a timeless way of thinking about the frequency of occurrence for each). And because there is no time dimension, all of these instants exist simultaneously (or more properly, eternally).
Reconciling with our experience of temporal becoming
But why does it seem to us that only a tiny percentage of these possible states has been or will be realised? And why is it that they seem to us to be strung together by a causal history (notwithstanding apparent quantum indeterminacy)? Finally, why do we FEEL like we are moving through time or that events are flowing from the future to the present to the past?
The answer starts with this: all of the most probable states (again, as determined by the universe's wave function) are what Barbour calls 'time capsules' in that they contain 'records' referencing an apparent past. These records include fossils, books, empirical test results and artefacts. More important, they include human brain configurations that contain memories.
Barbour reminds us that any conscious access to 'the past' is through CURRENT brainstates. In any instant a brain state is nothing but a small bit of the universe's overall configuration and but one of the many records potentially contained in that instant. Barbour must also intend (although I don't recall him saying it explicitly) that 'time capsules' are specifically those configurations that contain overwhelmingly (although not necessarily perfectly) CONSISTENT records. Otherwise, if we lacked a significant degree of inter-subjective agreement, or if physical records pointed randomly in different directions, life would be very difficult and confusing.
Another thing Barbour doesn't (as far as I could make out) make clear is whether the configurations to which records refer are in themselves time capsules. If not, then the configurations (and the records' referents) still EXIST, because all possible configurations exist, but the records are in a sense false, because the apparent past to which they point is not a likely one. If the configurations to which time capsules point ARE time capsules themselves, then there is a linked path of time capsules through Platonia, and our memories are 'true' in a sense they would not otherwise be.
As for our feeling of temporal becoming, Barbour puts that too down to brain states and the notion of the specious present, familiar to phenomenologists. I wrote about the specious present (retention, protention and the immediate now) in The Anatomy of Experience, so I won't go into any detail here. The bottom line is that each instantaneous brain state contains not only the current input from the world but also a record of the last brain state, and within that of the one before, etc. This recursive encoding of records in our brain states accounts for our subjective experience of the flow of time, of temporal becoming. But, says Barbour, just like longer-term memories, this feeling is actually wholly contained in each single instant, so long as that instant is one of the probable ones he calls time capsules.
Do I buy this?
Now, although I have a lay interest in physics and read a fair bit about it, I obviously am not at its cutting edge, so I can't comment on the technical aspects of Barbour's theory. But here is what I think of it at the level at which I can engage. I am on record elsewhere as arguing for realism and determinism in the interpretation of quantum dynamics. Barbour's view is a probabilistic one and therefore not deterministic, so my instincts lean away from it. But his equating our experienced states with those that are most probable (maybe by a vast margin most probable) goes some way toward alleviating my discomfort. If time capsules are, by definition, the states 'awarded' highest probability by the wave function (as it overlays the structure of the configuration space, Platonia), then our specific history IS given a special, privileged position, one that arises directly from the structure of Platonia. But I'm not quite sure whether Barbour is saying this.
My biggest questions are those alluded to three paragraphs above. Are the many instants that are referenced in the records at instant T, time capsules, as instant T is? Are the records in instant T-3 the same as those in instant T, except that they exclude reference to instants T-2 and T-1? If the answers to these questions are 'yes' then I think Barbour's proposal could be a sensible one, and I'm willing to throw away the dimension of time. My comfort arises from the fact that Barbour would then be assigning to the wave function (as influenced by the shape of Platonia) the ordinal role we normally assume to be performed by time. From a practical perspective, the upshot would be the same as in the block view of time that I have endorsed - all that IS, exists eternally. The STRUCTURE of the universe is set, and it is a peculiarity of our experience that we seem to flow through a time dimension. In either case, the god's eye view is of an eternal structure (one in Platonia, the other in 4-dimensional space-time). I'm not saying that there are no differences between the two - there are very big ones, especially for physics. But at the level of philosophical implication, I think that they are quite close.
If the answer to either question above is 'no', then I have a hard time swallowing the theory. (This of course doesn't mean the theory is wrong, and it needn't bother Barbour at all!.) If the instants, the configurations, of existence are not related to one another consistently - whether via a neatly stacked vertical causation or via consistent reference among configurations jumbled loosely 'in a bag', then there might as well be (and may indeed be!) only one instant. This is certainly philosophically possible, but it makes me want to go to bed and not get up again. (But this is what the determinism that I expound does to many other people, so there you go!).
For a more coherent and/but much more technical analysis of The End of Time by a philosopher of science, see Jeremy Butterfield, of Oxford University.
Originally posted 9 May 2005. My view shifted less than a year after writing this, when I came across Julian Barbour's The End of Time. Still, this was a step along the way. I guess my present view isn't far off what is expressed here briefly as 'Presentism'. But in another sense it is a special case of a B-Theory, with no 'real' flow of time.
I have for some time held a 'Block' view of time, without realising that it had such a name. Upon thinking a bit more about time, I realised that my view on it is so closely entwined with my views on personal identity, determinism and morality that I really should make it a matter of record.
The Block view at a glance
By a 'Block' view of time, I mean this: that time can be seen, within limits, as a space-like dimension that, when visualised in conjunction with the three spatial dimensions, creates a four-dimensional 'Block' of spacetime. This Block is the vessel that contains the complete history of everything - or simply IS the collection of all histories - in our universe. If space or time is infinite (as it now seems at least space is), then this Block too is infinite. This, I think, is the standard scientific view of time, and four-dimensional spacetime is the stage on which Einstein's general relativity is set out.
But there are potential problems with this. From a scientific angle, at least one of the leading candidate theories of quantum gravity - the required next big step in reconciling relativity with quantum theory and advancing our understanding of the universe - does away with spacetime altogether. From a philosophical perspective, some say that such a view fails to account for the flow of time. Leaving quantum gravity for another time, I'll concentrate hear on the philosophical issues.
My Block view falls under the umbrella of what is known as the B-Theory of time. There is another set of theories that fall under the A-Theory umbrella. Essentially, I think that the key differences are these:
A-theory and B-theory of time
The A-theory believes that the flow of time (temporal becoming) is real, objective and absolute. NOW is a moving instant that flows at one second per second. The A-Theory also believes that the temporal properties of futureness, presence and pastness are real temporal entities. A specific version of the A-Theory, Presentism, denies the existence of past and future, leaving only the eternal NOW. See my post on Eckhardt Tolle's The Power of Now.
The B-Theory holds that past and future events, like present ones, are real. As a matter of fact, B-Theorists hold that, just like there is no objective special place called 'here', there is no objective special time called 'now'. There are just points in the temporal dimension at specific dates and times, and the only real temporal entities are the temporal RELATIONS of earlier than, later than and simultaneous with. The image is one of a time axis on which we can see that some points lie to the left of (and are hence earlier than) other points. But the thing to grasp is that events that lie to the 'left' and 'right' of the time we presently occupy are just as real (at those times) as the events we witness now. And it goes further.
The philosophers discuss time mainly by talking about the truth of statements about temporal relations. For B-theorists, if my mother kisses the US President at 12:30 pm on 5 December 2003, then the statement, "D's mother kisses the US President at 12:30 pm on 5 December 2003," is true not just at 12:30 pm on 5 December 2003, but eternally. Eternally in this sense does not mean 'at all times' but rather timelessly. That truth, like the truth 2+2=4 does not exist in time at all.
A closer look at the Block view
But talking about truth values of statements doesn't do it for me. I want to talk about the existence of things and events. I am drawn, and have been since long before I read about the philosophy of time, to an image of spacetime, as seen from a perspective OUTSIDE spacetime. Of course, such a perspective cannot be attained, but we can think of it as a God-like one. From outside spacetime (and therefore necessarily outside time), we 'see' a four dimensional container, and that container holds the entire history of every particle, field and every other entity. If we were to pick out a single rock, we could follow it along the time dimension (which, since we can't visually represent 4 dimensions very well, we might think of as going from left to right) and see that it's spatial position shifts (up, down, etc) as it moves 'forward' through time. Now, I've said we can imagine this God-like perspective, but the more important point is that this is how things are, although we cannot attain the proper perspective to see them this way.
Just as the philosopher says that the STATEMENTS 2+2=4 and "D's mother kisses the US President at 12:30 pm on 5 December 2003," ARE TRUE eternally, I believe that that rock and everything else within the spacetime 'container' (or collection) EXIST eternally. Once again, this isn't to say that they exist at all times; if we say that we are still thinking within the time dimension. The Empire State Building came into existence at a particular time and will no doubt cease to exist at some time. It is rather to say that anything that exists at ANY TIME, exists eternally, timelessly, from this God-like perspective, outside of the time dimension.
This visualisation I've used also helps show the main objection that B-theorists have with the A-theory: there is no special time in this 'vessel' labelled 'Now'. Time is just a fourth axis for the grid system.
But this simultaneously throws up the big problem that A-theorists have with B-theory: it doesn't adequately account for the Now-ness or presence of certain events. The vessel is filled with events, but why do some specific ones feel very different than the rest, i.e. why do they feel like they are happening NOW. B-theorists answer, once again, more in terms of the truth value of temporal statements rather than about events / things per se. But I am quite happy to take it that the events that are happening NOW as opposed to at some other time are those events that are near-simultaneous with my asking 'Which events are happening now?' Events that happened in the past are those that happened earlier than my asking that same question, and future events are ones that happen later than when I ask the question.
What makes time unique among spacetime dimensions?
But this does highlight another problem that many B-theorists have with my particular Block time version of there own theory. Time is obviously not a truly space-like dimension.
This is where the real mystery comes in, and perhaps it is a particular weakness in my theory that leaves me in this cul-de-sac having to throw up my hands and appeal to mystery... But I haven't seen anyone else bottom it out yet either.
We could say, and many philosophers do, that it simply is the case that the temporal dimension is qualitatively and irreducibly different from the spatial ones - objectively. Or we could say that it is not that different objectively but that there is something about the nature of sentience and consciousness that makes our inter-subjective experience of it seem different.
If we're willing to accept one of these explanations, what are the knock-on effects? Well, on my view, accepting the Block theory of time answers the free will / determinism debate once and for all. Although such a theory of time is not necessary for determinism to hold (an A-theoretical flow forward from a set of initial conditions according to fixed and determinate laws does the job as well), I think it is definitely sufficient. If all of history is captured in spacetime, with us just consciously 'riding' through the time dimension, then everything we do, we do necessarily.
I think that the block view also prompts interesting questions about sentience and consciousness, life and death. If all that exists does so eternally, and if the flow of time is simply something that we experience subjectively, then are we not eternally living those lives?
When I die as when I live, all of the moments of my life exist in that four-dimensional spacetime; if that window that moves along the time dimension, providing access to the 'present' as it rolls forward, is not objectively in the nature of the temporal dimension itself but rather in our experience of it; if no moment in time has a privileged position relative to all the others, then I live my life, from 16 June 1966 to the day I die, eternally.
That doesn't mean that I live my life over and over again. It doesn't mean retracing and taking different turns through supposed possible worlds, as it is always exactly the same. But it could mean that my subjective experience itself (or perhaps more exactly each and every moment of it) runs eternally between those two points on the timeline. My first sentient experience (probably even before birth) exists eternally. My last dying experience exists eternally. And so does every experience in between.
Maybe the whole history of the entire universe sits, still and unchanging, four dimensions. Maybe the only movement is the eternal subjective movement of sentience between the start line and the finish line of each sentient life in the temporal dimension. And the existence of that sentience, that subjective perspective, is just something that happens to be, arising from the relations among entities in that four dimensional space...
If so, then Nietzsche wasn't far off with his doctrine of the Eternal Return. Although he saw eternity as a never ending looping repeat of history, which is quite different from what I've spelled out, the recommendation is the same: live each moment of your life as if you will live it eternally. See my post on Nietzsche here.
I'm curious. I like looking beneath and behind the obvious, also looking for what is between me and the obvious, obscuring or distorting my view.