Why I don’t believe I’m a Spacetime Worm

comments 43

Imagine you’re having coffee with your best friend; for the sake of discussion let’s call her ‘Basil’. According to common sense, the whole of Basil is present with you in the coffee shop. (If you’re facing her then you probably can’t see the back of her head; but it, and the rest of her, are before you nonetheless.) Now there is a peculiar philosophical position – known as ‘four-dimensionalism’ – which denies this datum of common sense. According to four-dimensionalism, you’re sharing the coffee shop with only one tiny bit of Basil. And that’s because Basil is spread out over time; she is a ‘spacetime worm’.

Suppose Basil was born in 1992 and will die (let’s be optimistic) in 2092. If four-dimensionalism is true, then the human being that is Basil is a four-dimensional object stretched out over these 100 years. And thus only one tiny slice of Basil, one ‘temporal part’ of her, is in the coffee shop with you. As four-dimensionalist Ted Sider vividly put it, if you wanted to embrace the whole of somebody, you’d have to cling to them from cradle to grave.

It is clear that four-dimensionalism is counter to common sense. But many philosophers believe that modern physics, in conjunction with various philosophical considerations, give us reason to think that it’s true. In this post I want to share my reasons for thinking the view cannot be true; or at least for sincerely hoping that it isn’t.

The basic argument is quite simple:

  1. My conscious experience is not the conscious experience of a spacetime worm.
  2. Therefore, I cannot be a spacetime worm.

There is at least one thing I know with certainty to exist, and that is my own conscious mind as it is right now. That thing which I know with certainty to exist – my conscious mind – is currently having an experience of a table with a laptop on it, beyond that a window, traffic outside, and a couple arguing in Hungarian in the next apartment. I am certainly not experiencing events of my childhood or of my life at the age of sixty four.

Now consider a Philip-like spacetime worm which is stretched across (let’s hope) seventy or so years of time. That Philip-like spacetime worm is certainly not having the experience I have just been describing; if it is conscious at all it is having some kind of weird consciousness involving all of the experiences of my life. But that is not my consciousness; it is not the consciousness of that thing which right now I know with certainty to exist.

In a recent article Josh Parsons has drawn attention to this point, but offers a solution: I am not a spacetime worm, rather I am a temporal part of a spacetime worm. The thing which has my conscious experience, the thing I know with certainty to exist, is just one tiny slice of the Philip-like spacetime worm stretched over seventy years of time. This is a coherent view, and it might be true. But I hope to God it isn’t. Because on the four-dimensionalist view such temporal parts do not exist for very long at all. Human-like spacetime worms are stretched through fairly long periods of time; enveloping many temporal parts. But the temporal parts which could be plausibly thought to have human experience last no more than a couple of seconds each.

Thus, if Parsons is right, then my conscious mind, that thing I know with certainty to exist, won’t be around in a couple of seconds’ time. It will be replaced by some other conscious mind which will be very similar to it, which will share its memories, but which won’t be me: the thinking, feeling thing I know with certainty to exist right now. This is precisely the content of the fear of imminent death: the fear that I won’t exist in the near future. If four-dimensionalism is true, then there is a very real sense in which I am dying every second.

It is not yet clear whether scientifically-based philosophy can provide us with overwhelming reason to believe four-dimensionalism. Until matters become clearer, I reserve my right to hope that four-dimensionalism isn’t true.


The Author

I am a philosopher and consciousness researcher at Durham University, UK. My research focuses on how to integrate consciousness into our scientific worldview.


  1. Edward Look says

    Your STW is part of a greater block of 4th dimensionality, so in a sense your ‘slices’ exist for as long as the universe exists, as part of a greater system.

    • @Edward Look: What is of interest to me is that *I* – this thinking, experiencing thing — will exist in the future. Suppose I am a time slice that only lasts a second. It will be true that there is something in the future which contains me as a part. But still I — the part of the block that is me — will not exist a couple of seconds in the future. That’s horrible.

      • tom harrigan says

        The part of you that is “you” is as eternal as any other part of the block-universe, which contains your entire history.

      • @Tom I agree there’s a sense in which things in the block universe exist eternally (although a sense in which they don’t), and some people find comfort in that. I would be nice to eternally exist for more than a couple of seconds though! Moreover, it’s not clear that this does assuage the fear of imminent death. The content of the fear is *that I will not exist in the near future*, and that remains true even if it’s the case that in the future it will true that I exist in the past.

  2. But, it seems to me, your experience *is* the experience of a spacetime worm, viz, a temporal sequence of time-bound phenomenal properties. Pace Parsons, I don’t think an illusion is involved: you really are currently having your current Hungarian-argument-flavoured experiences, and no temporally distal ones. Which is just to say that the worm currently has only your/its current experiences, just as it/you currently have only your current beliefs, location, limb-count etc.

    Perhaps that position is easier for me to take because I’m a physicalist, and think your current experience is (more or less) a current state of your brain. But does a dualist/panpsychist have a reason to think the phenomenology of a worm should be tenseless?

    • @aboutel I read this as saying that the worm has my consciousness in a derivative sense, in virtue of having parts which have my consciousness. This is the sense in which the worm has 10 fingers and 10 toes. However, I am conscious in a non-derivative sense: there’s something that it’s like to be me.

      I don’t think there’s any difference here between the situation of the dualist/panpsychist versus the situation of the physicalist. Do you?

      • Adrian says

        I agree that the worm has your current conscious experience in something like that derivative sense. But it has your consciousness (tout court, lifetime supply) in a non-derivative sense.

        One might well think that means there’s nothing it’s like to be *me*, as in the entire worm (at best, what it’s like to be a worm is the sum of varying phenomenal characters over time). But that seems a harmless consequence. There’s something it’s like to be me now, and that’s all introspection seems to tell me.

      • @Adrian I know for certain that I feel pain now in a non-derivative sense. The worm feels pain now, but only in a derivative sense. Therefore, I can’t be the worm.

        It’s contradictory to say that the worm has my consciousness in a non-derivative sense, but that there’s nothing that it’s like to be the worm. You say the important thing is that there’s something that it’s like to be me now. But if I’m the worm then there’s something that it’s like to be now only in a derivative sense: I have a temporal part now such that there’s something that it’s like to be that temporal part.

      • Are you sure? 🙂 What’s the phenomenology of derivativeness? What I know through introspection, I take it, is that I have phenomenal properties right now. The 4Dist agrees with that. It’s just that—for metaphysical reasons to do with the nature of time, temporary intrinsics, etc—the referent of “I” includes the 7yo in 19mumble with quite different phenomenal properties. I don’t see how that metaphysical (or semantic, but not phenomenological fact) inconsistent with my introspective knowledge. Why do you think it is?

        (I don’t think there’s a contradiction there. If there’s nothing it’s like to be the worm, it’s in the sense that there is no *single* phenomenal state that characterises the worm. The worm has plenty of phenomenal properties.)

      • Something that is ‘conscious’ in a merely derivative sense isn’t really conscious, it’s merely conscious in the sense that it has parts that are conscious. It’s not true to say ‘there’s something that it’s like to be it’; it’s merely true to say ‘it has parts such that there’s something that it’s like to be those parts’. If to have a phenomenal property is to have a conscious state, then the worm doesn’t have phenomenal properties; it merely has parts that have phenomenal properties.

        There’s perhaps a confusion, as when we’re thinking of spatial parts and wholes, it’s very natural to assume that the whole in some sense ‘inherits’ to properties of its parts. Perhaps the worm does inherit some kind of consciousness from its parts; but if there’s something that it’s like to be the worm it’s nothing like what it’s like to be its parts.

      • The sense in which the worm has your total consciousness, as I see it, is just that that history of phenomenal states is a property of it and not any of its parts—just as its 4D shape is a property of it and not of any temporal part. So it has that total consciousness non-derivatively. (It supervenes on the stages’ phenomenal properties, just as its shape does on its parts’ shapes, but that’s a different thing.)

        I’d still like to hear more about the phenomenology of derivativeness—what is it about your experience that tells you it’s not the experience of a temporal part?

      • I’m not sure what it means for a ‘history of phenomenal states’ to be a property of something. All I can make of that is that the worm has parts which together instantiate all the phenomenal properties of my life history, but that just entails that the worm has phenomenal properties in a derivative sense.

        There is no phenomenology of derivativeness, because something which is merely derivatively conscious isn’t really conscious, at least not in the original meaning of the term ‘consciousness’ (according to which something is conscious iff thee’s something that it’s like to be it). It’s merely ‘conscious’ in a sense distinct from but connected to the original meaning of the term (its ‘conscious’ in the sense that it has parts such that there’s something that it’s like to be those parts). So I know I have non-derivative consciousness simply because I know that I’m conscious, in the original sense of that term.

        For what it’s worth, I think David Lewis would agree with me on this. He concedes in response to Haslanger that worms aren’t ‘just plain round’. What was important to him was simply that something in his ontological was just plain round, namely the temporal parts. In the 4D world the worms aren’t ‘just plain conscious’.

      • I think one can overstate the difference between wholes and parts, as well as understate it. Say there’s a point at which my leg is three inches wide. That’s not my *width*, because I’m not my leg; but being three inches across there is still one of my spatial properties. Indeed it had better be one of my spatial properties, because it’s a component of my overall shape, which is not a property of any of my (proper) spatial parts. Analogously, the worm isn’t simply round, it’s round-at-t. But it *is* round-at-t, it really is spherical there/then, and moreover that roundness-at-t is a component of the 4D shape that the worm has and its parts don’t. Also analogously, I suggest, the phenomenal properties of each temporal part are (time-local) phenomenal properties of the worm, and components of its (non-time-local) overall phenomenal history.

        But I can set all that aside, and grant that the worm has no consciousness in the relevant sense. I still want to know how you can tell by introspection that it is *you* that is conscious, and not your current temporal part. To put it another way: how would your experience be different if it was your temporal parts that were conscious?

        It seems to me that what would happen in that case is what does happen, namely at each time the phenomenal properties proper to that time, and only those, would be available for introspection. What do you say would be different?

      • I agree that I have the property of being three inches in a certain location, but only in the sense that I have a part which is three inches in such and such a location. Analogously the worm has my pain, but only in the sense that it has a part which has my pain.

        I know that it is me that is conscious because my stipulation what I mean by ‘me’ in this context is ‘this thinking feeling thing’, which I pick out in the Cartesian way. I agree that that thing might be a temporal part, but that leads us to the radically skeptical scenario that ‘I’ — this thinking, feeling thing — won’t exist in a couple of seconds time. Could be true, but I hope it isn’t.

  3. I love to think about this. Peirce has an argument against the idea of there being a “now” that is seperate from the rest of time. 1. It is implausible that now is a point in time because it takes longer that zero time to have a thought. 2. If now has duration then there are some bits of now that are later than other bits. 3. Any set time for now is arbitrary. His conclusion is that time is like space and our experience is more and more intense the closer we are to now. memory is a direct experience, although of something distant. Distance creates a kind of probabilistic dimmness. In our performance philosophy workshop last tuesday someone said that the future is absent. It seems to me that you account of your present experience includes a lot of encoded information from the past, for example identifying someone as Hungarian.

    • @Johnny Sure, my current conscious experience involves information learnt in the past, memories being the most obvious case (or rather Parfitian Q-memories if I am a single temporal parts).

  4. Nino Kadic says

    I have three questions:
    1. Could you explain a little bit more why you assume that the conscious experience of a STW must be different from your experience? Simply assuming that it must be different seems question-begging.

    2. In the penultimate paragraph, you say that your conscious mind gets replaced every few seconds. But why is psychological continuity a special problem for four-dimensionalists and not for presentism?

    3. On fear of death: If death is but a moment in the complete existence of an individual, then we have less reason to fear it. It seems that four-dimensionalism is more comforting than presentism, where the whole of you dies in one moment, right?

    • @Nino
      1. The point is that the worm only has my conscious experiences in a derivative sense: it is conscious only in the derivative sense of having temporal parts which have my conscious experience. But I am conscious in a non-derivative sense. Perhaps the worm has some peculiar kind of consciousness which involves a unified experience of all my life experiences, but that’s not *my* consciousness.

      2. The presentist can hold that the thing which has my consciousness right now is numerically identical to the thing which had my consciousness a minute ago. But according to 4D the thing which has my consciousness right now — i.e. the temporal part — didn’t exist 5 minutes ago, and won’t exist 5 minutes hence. The worm existed 5 mins ago, but it has my consciousness only in the derivative sense that it has temporal parts which have my consciousness.

      3. Fair point, some people do find it comforting that I exist tenslessly if 4D is true. But it seems to me cold comfort if I am forced to the view that I – this thinking, feeling thing – only exist for one tiny moment of time.

  5. Alan says


    Came across this recent article by Bernard Carr (cosmologist) on Time and Consciousness. He’s talking at “How the light gets in” Festival this coming Friday 3 June. I hope a video gets posted!


    “For in the ‘block’ universe of special relativity, past and present and future coexist. The 3-dimensional object is just the constant-time cross- section of an immobile 4-dimensional world-tube and we come across events as our field of consciousness sweeps through the block. However, nothing within the spacetime picture describes this sweeping or identifies the particular moment at which we make our observations.”

    And if there’s something quantum about consciousness doesn’t that go even further away from the STW? Kind of more creative and becoming about consciousness than fixed.

    • Thanks for the reference Alan, I’ll check it out. The implications of quantum mechanics for time are less obvious to me than the implications of special relativity, although I’m open to suggestion.

      • Alan says

        Re quantum mechanics and time. A little off topic re STWs but John Wheeler’s suggestion of a quasar emitting a single photon which could pass either way around an intervening galaxy between the quasar (say 1 billion light years away) and Earth. The path being determined by an observation on Earth (it has no path until observed). So there’s a kind of “reaching back” into the past by the observation to determine whether it went path 1 or path 2. A quantum mechanics effect. Common sense says it must have had a path before the meas. but QM defies common sense. Also AFAIK causality isn’t violated though it seems so.

        If we “scale up” to people and consciousness doing stuff over time I’d guess we still get some effects like this, we are not just classical physics objects in the sense of just relativity and world tubes (where QM is not included). So seems not strictly classical relativistic space time worms.

      • I’m not necessarily opposed to things that are counter to common sense. I defend views which most people think are wildly counter to common sense. One main thing I push for is that we have a source of evidence that goes beyond what we know about scientifically: our immediate knowledge of our own conscious experience.

        I think that knowledge rules out the possibility that I we are spacetime worms. It does leave open the possibility that we are temporal parts of spacetime worms. The problem with that possibility is that it’s not only counter to common sense, it’s also terrifying, as it entails that I won’t exist a moment hence. It could be true, but I hope it isn’t.

  6. Greg says

    1*. I have my conscious experience non-derivatively
    2*. Spacetime worms have their conscious experiences derivatively
    3*.Therefore, I cannot be a spacetime worm.

    That seems to be the argument to me, at least, they’re the hidden premises behind (1).

    I guess my question is what is the justification for 1*? It seems to me that phenomenologically speaking you and the 4D theorists have the same data. You will say ‘it seems to me that i have my experiences non-derivatively, therefore I have them non-derivatively’, whereas the 4D theorist will deny that’s a valid inference i.e. they don’t buy into a ‘seems is constraint’ on all aspects of our experiences. Seems fair enough, I think you can make an argument from this somehow. But, it also seems open to question whether, when I do introspect my experiences, I do seem to have them in a non-derivative sense. I mean, I have my experiences, but what is that part/aspect of my consciousness which I can introspect and say ‘yes, that shows I have them non-derivatively’.

    My second question is: doesn’t the cosmospsychist say that we have our conscious experiences derivatively? Roughly they say ‘I have my experiences in virtue of the cosmos having them’, and that seems to be derivative in the same sense that the panpsychist would say we have our experiences: ‘I have my experiences in virtue of my parts having them’. If so, then the cosmopsychist can’t hold 1*, no?

    • @Greg. Yeah, maybe that’s a better way of putting the argument. On the first point, see my discussion with Adrian, who makes a similar objection. On the second, cool point but…I think there’s too senses of ‘derivative’ in play here. First sense (employed in the context of cosmopsychism): ‘derivative’ consciousness is just consciousness that’s grounded in something else. Second sense (employed in the 4D discussion) something with derivative consciousness isn’t ‘conscious’ in the original sense of the term: there’s nothing that it’s like to be it. Rather it’s ‘conscious’ in some secondary sense; specifically its ‘conscious’ in the sense that it has parts that are conscious.

  7. We might be about to recap some of the exchanges above, but I can’t see why you aren’t making the same mistake Lewis made when he argued there was a ‘problem of change’ for eg apples and redness. Here the natural solution (I take it we agree) is to recognize that redness is a time-indexed property of apples.

    You say you don’t want to allow that consciousness is similarly a time-indexed property of people. But, on the face of it, it surely is. I am conscious now, but wasn’t last night. (There is no need for you, as a 4-dist, to view this as a derivative property which depends on the properties of your temporal parts–it can be a primary (though time-indexed) property of your whole self.)

    However, once we have consciousness as time-indexed, then it seems open to the 4-dist to say that what introspection shows is that I (the whole worm) am conscious-now (without getting into the ugliness of saying that ‘I’ refers to a time-slice who is conscious simpliciter but dies sooner that a damsel-fly . . .)

    • The troubles don’t arise at the point when we say my conscious properties are time-indexed. They arise when we ask how the 4Dist analyses that fact. They analyse ‘PG is conscious at 4pm’ as ‘PG has a temporal part which is conscious at 4pm’. But that means that when they say ‘PG is conscious at 4pm’ they are not using the word ‘conscious’ in the original sense of the term, i.e. they are not saying ‘There is something that it’s like to be PG at 4pm’. Rather they are using ‘conscious’ in a secondary sense to mean ‘has a part such that there is something that it’s like to be that part’. But I’m ‘conscious’ in the original sense of that term: there’s something that it’s like to be me.

      (Actually I’m sympathetic to Lewis’s argument against non-presentist endurantism too, for reasons I gesture at in chapter 10 of my book, but that’s another story…)

      • Well, perhaps I’m not clear about what it takes to be a 4-dist. Your 4-dist sounds a bit like a stage theorist to me. Still, let’s not worry about classifications. What about somebody who thinks people are s-t worms, but is perfectly happy to have terms like ‘PG’ referring to whole worms? Why would they have to analyse ‘PG is conscious at 4pm’ as saying anything about temporal parts, as opposed to simply saying that the whole worm is conscious-at-4pm (in just the sense that you 3-dists will say that the apple is red-at-4pm, or indeed that PG is conscious at 4pm)?

      • Hmmm…I suppose you could be a 4Dist who thinks that whole worm has time-indexed properties that aren’t reducible to properties of temporal parts, and that would indeed get round the problem I’ve raised. However, you’d then lose one of the main motivations for being a 4Dist, i.e. David Lewis’s problem of temporary intrinsics. You might as well just be an eternalist 3Dist.

        So maybe if you’re going for that view (because you have some other reason for being a 4Dist?), then I’d have to drag out my support for Lewis’s argument from problem of temporary intrinsics against non-presentist 3D forms of eternalism (which I think would also apply against your odd form of 4Dism). Lewis starts with the premise that shape is not a relational property. I don’t buy that premise, because we don’t know what shape is a priori. I run the argument instead with the premise that consciousness is not a relational property (we do know what consciousness is a priori). Your response to that argument would be to deny that we know what consciousness is a priori. So we’re back to the disagreement over transparent phenomenal concepts.

        Interesting…real progress there I think… 🙂

  8. yossariansmith says

    It seems to me that your trouble stems from the idea that the world is innately divided up into distinct well-defined entities, of which you have to be one and not more than one. So, in this worldview, you have to be precisely one of the timeslice, or the s-t worm, or some other thing subject to a non-4D-ist version of time. This seems to me to be a false assumption. I’d contend that the way we divide up the world into ‘entities’ – people, objects, etc – is driven not by the world being actually composed of these metaphysical things, but by the fact that dividing the world up like that is useful to us. But the world doesn’t come like that. There can be different ways of dividing it up that are objectively useful for different purposes, and don’t involve falsehood, in much the same way that length (which is real and prior to our investigation) can be measured in metres or feet (which are artificial and invented because they are useful units of measurement). It seems to me that arguing about whether ‘I am’ the timeslice, or the worm, or some other thing, is like arguing about whether feet or metres are the ‘true’ unit. Let me explain why I think this analogy works.

    What you are given is what you refer to as your own conscious mind as it is right now. But this formulation looks like it contains certain assumptions about distinct well-defined entities – ie. that there is precisely one thing that is ‘your mind’. I don’t think this is given, I think this is surmised. What ‘you’ undeniably have is ‘some consciousness’ – whether that consciousness is one thing, or part of a thing, or many things is not immediately given. You (and all of us) then go on to delineate ‘yourself’ around that lump of consciousness. You are then emotionally invested in that extended ‘entity’ and the precise location of its boundaries. But we have a bunch of specific, identifiable reasons for/causes of positing such an entity, none of which (that I can think of, at least) have a great deal of metaphysical persuasiveness. For example: we want social status, social status presupposes a ‘self’ to be the object of the status, therefore we must believe ourselves to have a ‘self’. We want to survive (for obvious evolutionary reasons), therefore there must be a ‘self’ to keep alive. We love our children, therefore there must be a distinct, reidentifiable child for us to love, which must coincide with the living physical object that carries our genetic material. There are sundry good evolutionary reasons for human animals to think of themselves and each other as distinct, reidentifiable, singular entities – and this should make us suspicious of the claim that that’s what we actually are.

    To back up this suspicion, it’s entirely possible to come up with coherent alternate ways to construct ‘people’ (loci of agency, holders of status, etc) around clumps of present-moment consciousness. Along with the aforementioned timeslices and worms, we might attribute agency to ideas, rather than people, for example – human bodies being the passive battlefields within which ideas battle for control. The reason we don’t is probably twofold – first, it’s very hard to see what a person really believes/what ideas really control a body, as in either case lies might come out the creature’s mouth, making identification of agents much harder; second, as I mentioned before, parental love posits a child that enters the world somewhere between conception and birth, leaves it at that body’s death, and stays in that body for the intervening period, which makes it incompatible with this hypothetical view of things. These are good reasons not to use it, but they don’t render it incoherent – only less useful.

    A similar consideration can be applied more broadly to the different philosophical conceptions of time itself. The 4D model of time is clearly coherent with the world we (seem to) live in; I must confess I struggle to understand other models, but in the absence of conclusive arguments against them I’ll assume they cohere with it too. Like metres and feet, therefore, the clash between them should not be thought of, prima facie, as a disagreement over which is true, but over which is useful.

    • @Oliver Thanks for extended thoughts! Suppose I see a fly bashing against a window, and I wonder ‘Is that things conscious, is there something that it’s like to be it, or is it just an unfeeling mechanism?’ Seems like a coherent, difficult to answer, question. Suppose I decide it does feel; I might then ask ‘What precisely is it that feels, the fly or some part of the fly’. Similarly, we can ask of a human being: what is is that feels, the whole organism, or its brain? Do you think these questions make sense? I can’t see how the answer could depend on human categorisation. Similarly I think I can ask ‘What is it that has the feelings and experiences associated with me? Is it the spacetime worm, or is it a slice of a spacetime worm, or neither?’. And again, I can’t see how the answer could depend on human categorisation. You might be right about other conceptions of the self, but I can’t make sense of your view with respect to this conception of the self, i.e. the thinking, feelings thing I’m certain of the existence of.

      • yossariansmith says

        Well, suppose I see a mountain. I might ask, ‘is this patch of earth part of the mountain, or not?’ If the patch of earth is clearly in a valley, the answer is ‘no’, and likewise if it is obviously on the mountain, the answer is plainly ‘yes’. It makes sense to ask the question. But if the patch of earth is somewhere in the mountain’s foothills, for example, there is no yes-or-no answer – the right answer is ‘I guess kinda?’ The world is not divided into two sets, ‘things that are the mountain’ and ‘things that are not’. ‘The mountain’ is simply a useful category for us humans to think with. Likewise, ‘the self’ is a useful category, but we can’t get infinite precision out of it: we can say truly that the fly’s legs aren’t part of it and its brain is, but when we come to look at its temporal parts we are rightfully at a bit of a loss. In that respect it’s not a natural kind, in much the same way ‘a mountain’ is not a natural kind: it’s a useful category, but it has places where its application is necessarily unclear, and we can in principle fully explain the world without it.

        The way this connects to your worries about consciousness is that we can definitively say that such-and-such periods of a human life are conscious – that being, given some plausible assumptions, scientifically verifiable – but we can’t go on to distinguish between fixed, distinct conscious entities. In neither the 4D model nor the alternative are the boundaries of consciousness very much in question; what’s in question is who, exactly, is conscious. What I’m claiming is that the boundaries of ‘who’ are like the boundaries of the mountain, rather than the boundaries of consciousness being like the boundaries of the mountain – but the boundaries of ‘who’ seem to be where your worries arise, if I’m interpreting you correctly.

      • I might agree with you when you talk about mountains, and certain concepts of self, but I just can’t see how it’s supposed to work when it comes to consciousness. Do you think it’s dependent on human concepts which part of the brain is conscious?

        Take the pain in my knee right now. I want to know which material thing is feeling that pain: a temporal part or a spacetime worm. Notice that I haven’t used the concept of self at all. It seems to me that there must be a definite answer to that question (just as there’s a definite answer to the question of which part of the brain has consciousness). I can’t make sense of the idea that how we answer that question depends on which concepts we use.

      • yossariansmith says

        I’d contest whether we could definitively pick out which part of the brain is conscious beyond a certain level of precision. We might have to zoom in to the level of neurons’ internal structure to find the fuzziness, but my money says it’s there. So to that extent, the mountain and the brain could (as far as we know) be analogous.

        But the case is actually a lot easier when it comes to temporal parts, spacetime worms and so on, because whereas the brain is very different and easily distinguished from its surroundings, any given moment or period of consciousness merges quite smoothly into its predecessors and successors, including states of unconsciousness. (I have a friend who gets insomnia because the segue from consciousness into sleep freaks him out on a conceptual level.) So although for practical purposes there’s really only one way to draw a spatial boundary around the locus of your consciousness, there are no such strong guidelines for the temporal boundary short of death. That means the temporal boundary of the conscious thing in the 4D model is much more concept-dependent than its spatial boundary.

      • I think there might be a certain conflation of epistemological and metaphysical considerations in your first paragraph. Just because we can’t *know* precisely which bit of the brain is conscious, it doesn’t follow that *in reality* there’s no fact of the matter as to which bit of the brain is conscious.

        But even if there’s a certain amount of indeterminacy as to precisely which material entity has my consciousness, I can’t see how it could be indeterminate whether the temporal part or the spacetime worm has my consciousness. Can you help me make sense of that?

        Compare: it’s not completely determinate which material object is ‘Mount Everest’ (e.g. it may be indeterminate whether or not to include or exclude a rock near the bottom). But there’s a completely determinate answer to the question of whether Mount Everest is in Japan. Likewise, even if it’s slightly indeterminate which precise physical object has my consciousness, I can’t see how it could be indeterminate whether it is the temporal part or the worm (they’re very different physical objects).

        What you say about experience over time sounds plausible, but I don’t see how it helps with the claim you want to make.

      • yossariansmith says

        OK, let me make a slightly weaker claim: on the 4D view, I can concede that the physical entity that has your-consciousness-as-it-is-now can be outlined as easily as the mountain, and (on said 4D view) is pretty plainly the timeslice rather than the whole worm. But your evaluative conclusion – that you yourself will die with the timeslice and that this is therefore bad – does not follow, because it relies on the equation of ‘yourself’ with ‘the physical object that has your-consciousness-as-it-is-now’. The latter is well-enough-defined temporally on the 4D model, but the former is constructed subject to the definitional foibles I pointed out in my original comment, and thus is not – or need not be – the same thing. What you care about is yourself, rather than that physical object, and since that self is constructed in a manner more than flexible enough to encompass multiple timeslices, the transience of that physical object, the timeslice, is not sufficient to ground your horror unless you (choose to?) construct your self in a rather perversely masochistic way.

  9. Andy says

    There are some interesting ideas here. Consider that your conscious self need not necessarily cease to exist as the current moment passes. It could be that the consciousness you identify through introspection is not simply bound to (nor equal to) a

    single 3D space time slice of the worm. It could rather be an observer of the worm that moves along the worm’s length. If you consider this observer to be external to 4D spacetime then that could be construed as a form of dualism, though a hardcore

    physicalist might still be willing to accept its existence as some sort of physical property. This observer traces a straight line along the worm’s length, but the observer itself likely has zero dimensions. If you equate the conscious observer

    with the one dimensional line then you’re back to looking at something very similar to the 4D worm itself, prompting the same discussions you have had, but if the conscious observer is a zero dimensional point that is always in motion along the

    line, it apparently can mean you will not cease to exist as each moment passes; rather your conscious point of view itself traverses those moments. The 4D universe itself and the worm are static, with no present moment and no movement. It is your

    conscious perspective itself that moves and defines each present moment.

    yossariansmith raises interesting points around the boundaries of self perhaps being arbitrary human classifications. Consider that your qualia, your thoughts and sensations, seem to be closely associated with neurons firing in your brain.

    Information in the neurons is vividly accessible because of many strong connections between the neurons, electrical and chemical connections. Consider also though that the brains neurons are connected to other organs in your body via nerves and

    that these also relay information. Further, the rest of the universe interacts physically with parts of your body in a similar manner, again transmitting information. At this level the interactions are perhaps somewhat less hectic and the causal

    links to the firing of your brain’s neurons become weaker as do your brain’s influence on the events that affect them. However, these other parts of the physical universe are still connected to what you call yourself and they are

    still apparently shaping your qualia. The boundaries of the body and brain and the information in the mind have therefore become somewhat fussy at best and outright arbitrary at worst. What we are left with at least is you can still say that you

    appear to be centered in your brain. Your first person perspective exists here and now. This is where the activity I have been describing seems to be the most concentrated, the centre of your reality, or for the solipsist, the whole

    of reality. But this centre is the point location in spacetime that seems to traverse the 4D universe, centered on the 4D worm.

    The difficult thing, as I think you’ve identified, is that there doesn’t seem to be any evidence that the conscious self persists from one moment to the next. It might do, but it also might not. It also goes almost without saying that there could

    be a multitude of conscious dots all traversing your worm at different points simultaneously. Similarly if you add a quantum Many Worlds idea, there could be countless more.

    • yossariansmith says

      Your dot-traversing-the-worm account is interesting but a little odd, because it seems to presuppose the falsity of the four-dimensionalist account, making the worm redundant – the reason being that the dot is moving over time in a non-dimensionalist way, so one might ask ‘if the dot can do that, why can’t everything else?’ (A very similar objection applies to the growing-block theory: if the height of the block can change over time, then what’s the block for? You’ve already got time working before you introduce the block!) More broadly, I think from a timeless perspective time must always look like a dimension simply because you can line up the moments in order and look along them ‘all at once’, which is what you’re not doing with the moving dot. If you were to do so, it would not be a dot but a line, repeating the problem again, as you point out.

      • Andy says

        The moving dot doesn’t make the worm redundant (In a similar way I am not convinced that the growing block is redundant when compared against a complete, fully grown block) because the dot is what adds a subjective present moment to the universe.

        You may respond by saying that all possible present moments are already contained in the 4D worm itself (which would be true, for the lifespan of the being), but that still does not make the dot redundant, because we still need a way to pick out one single indexical location in time (and space) to attach an individual’s first person perspective.

        My understanding of the growing block theory of time is that it entails the concept of an objective, universal present moment, which is slightly different. I’m saying nothing on whether that exists, simply that consciousness requires the existence of one or more subjective (i.e. first person) present moments.

        From a dualist perspective, the complete, eternal 4D spacetime and the worm within it are physical, but the dot and its associated present moment are perhaps metaphysical.

        A slightly whimsical analogy might be to think of the 4D worm as a record which encodes an entire symphony but which cannot be experienced without placing the stylus (our 0D dot) at one point on it’s surface and setting it in motion.

      • yossariansmith says

        I understand what the dot is for. The problem I have is that the dot right now – the present moment of the dot – is specially picked out on the worm, simply as being present. This means the past and future versions of the dot are in that regard not specially picked out – but they will be, when they are present. But that means we have multiple different versions of the worm – the worm now, and the worm later, each of which has a different specially-picked-out dot. Therefore, time =cannot= be the long axis of the worm. If it were, then halfway along its length, the worm’s specially-picked-out dot would be halfway along its length, but three-quarters of the way along, the dot would be three-quarters of the way along. This is plainly contradictory. So one of two things is happening: either the worm in its entirety is changing along its time axis – which is as incoherent as supposing that a baguette in its entirety could change along its length – or the worm is changing over some kind of time that is =not= just its ‘time’ axis, meaning that it does not explain time at all, and so is entirely redundant.

        This is exactly analogous to the growing-block business, more or less by straight substitution of terms, so perhaps this will make my point clearer: to say the block is different lengths along its length is plainly incoherent, so to say it is different lengths at different times is to imply that its length is =not= time. But the whole idea of the block is that its length is time. Therefore, the growing-block model is logically contradictory.

        You can have a 4D block that grows over time, of course, but it’s just a block, it’s not spacetime. Likewise, you can have a 4D worm that a dot moves along over time, but it’s just a worm – it’s not your literal present, past and future, any more than the top and bottom ends of a baguette would be the literal past and future of a dot moving along it, even if the dot could only experience a 2D slice of the baguette at any one time.

      • Andy says

        I see the implications of your objection now.

        For a dot to be literally in motion along a 4D worm, it would have to be moving along some dimension and if that dimension were time, it’s not the same dimension of time that the worm’s length represents, otherwise it would be a line. Possible solutions to this might include that the dot is actually moving along a 5th dimension, but I have spotted the greater problem with this idea.

        The dot’s motion appeals to our intuitive understanding of the physical world, where we believe that a physical object that has moved from one location to another (importantly, before our eyes) is still the same object, when in fact the moving dot is just as vulnerable as the 3D time slices of the worm are to Professor Goff’s argument that they might not be the same entities (in the sense that they might not still be him). Further, I see that all entities that undergo a translation are vulnerable to the same attack, for example we do not know whether a car driving along a road is really the same car or an infinite number of different 3D car “slices” that are not the same object. This is the question of diachronic identity. Of course, in the physical world most of us have no fear that the car that exits the road might not be the same car that entered it, but I do now see that my moving dot in itself confers no extra protection to the identity of Philip’s consciousness over time. The only protection it confers is the one that I stipulate when defining the dot, so I do see that in that sense I am begging the question and I also do see some sort of redundancy in that I could have simply assigned a similar protection to one of the 3D time slices that had already been identified as part of the worm.

        What my experiment was really trying to illustrate is an idea of something persistent from one moment to the next that stores information about the identity of the Philip at the table with the laptop, so that that identity is preserved. Perhaps such a construct is unnecessary, if his first person perspective has an inherent persistent identity already, but if so I was merely trying to pick that out and identify it. I certainly wasn’t presenting evidence for its existence, but I never claimed to be. I can see how my model has a certain redundancy but the redundancy was introduced for emphasis, but I accept that this emphasis is not useful to everyone. I since found the author of this Wikipedia entry https://en.wikipedia.org/wiki/Static_interpretation_of_time describes something similar (unfortunately without a citation) “the universe is regarded as akin to a reel of film – which is a wholly static physical object – but which when played through a movie projector conjures a world of movement, color, light and change. In the static view our whole universe – our past, present, and future are fixed parts of that reel of film, and the projector is our consciousness.”

        Thank you very much for your responses, they got me thinking a lot!

      • yossariansmith says

        And thank you for yours! I grok the non-dimensional idea rather better now than I did before our conversation.

  10. Pingback: You Are a Space-Time Brain Worm: Why Brain Uploading is Murder but Abortion is Not – Greg Conan's Blog

  11. Pingback: You Are A Space-Time Brain Worm: Why Brain Uploading is Murder but Abortion Isn’t – Greg Conan's Blog

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