I feel like this question has a good chance of having been asked here before, but the first ten-odd "similar questions" listed by the site when I composed the title didn't cover what I'm aiming for, so I'm not sure. Will delete if it turns out to be a duplicate, anyway.

Also, the only SEP article I refreshed my memory of before composing this question is one about time in general. Could easily be addressed in e.g. the article about the metaphysics of causation. For now, my incomplete memory of the latter does not testify on behalf of said address, however.

So "caveat emptor," so to say...

Definition of causal determination at issue. Assume that the past and "half" the present function as constants relative to a variable future. The past/part of the present determine the future mathematically in the sense of "solving for" the variable of the future.

The four-dimensionalism consideration. Imagine a world consisting in a single tesseract whose fourth coordinate slot is timelike. Without supposing an absolute past, present, or future, we have all facets of the tesseract "given" in atemporal simultaneity.

It seems as if no facet, taken to be pastwise, "solves for" other facets as variables, since no facet is a variable as such. All facets are determined "at once" by whatever function projects the whole tesseract "at a glance." We can't step outside the tesseract (if we're inside of it) to say that the unit cause of the entire structure is itself an effect of a prior cause, etc. Perhaps this is possible in general, but for reasons of local empirical-causal closure, this fact transcends our possible empirical knowledge. And logically, it is impossible to predetermine the content of an information powerset from prior information sets; there is always underdeterminately more in an indefinite powerset than is in its base. So there is no a priori guarantee of determination either.

Question: so what use is the concept of causal determination in a four-dimensionalist closed world? A unit circle could be determined from x2 + y2 = 1 but no infinitesimal side of the circle "causes" the other sides to be so. And we have no knowledge that the formula for the unit circle must be an effect, so to say, of another formula, and so on "backwards in time." So is the notion of temporal determination, as A-series determination, required at all to interpret four-dimensionalism as such? Because it seems, here, not to be required at all.

  • Sorry to say, but there is a certain amount of word salad here. How would you define "the past" on a tesseract? What is "half the present?" A tesseract is a four space dimensions object, so where does time come in as a fourth dimension? How do you draw a unit circle on a tesseract? It is especially disheartening since all of these issues have been beaten to death in the study of relativity in physics. The idea of causality is quite well defined and even has a clear and experimentally robust version in relativistic quantum mechanics.
    – Boba Fit
    Nov 17, 2022 at 0:43
  • @BobaFit you're not familiar with four-dimensionalism, are you? The point of it is that a fourth dimension that is timelike is also spacelike because it's all really one concept of spacetime. If you understand geometry in the abstract the rest can be processed easily Nov 17, 2022 at 1:37
  • @BobaFit also, as I actually am on the schizophrenia spectrum, I'd appreciate it if you don't make false and ableist comments about word salad. CriglCragl obviously understood what I was saying and it's not that difficult to do so. Nov 17, 2022 at 1:43
  • Actually, I need to just quit this site. I'm not contributing anything worthwhile with either my questions or my answers and stressing myself out trying a zillion different ways to make my posts more relatable is making my condition worse. I just give up 🤷🏻‍♂️ Nov 17, 2022 at 2:09
  • @KristianBerry, I often find your questions interesting. When I can't understand them (about half of them, to be frank), I have never gotten the impression that you are talking nonsense; it is always evident that I just don't have the required background. And I'm pretty good at detecting nonsense. Nov 17, 2022 at 3:05

4 Answers 4


You might consider How does biological evolution work in the block universe/b-theory of time?

And on causation in general Is the idea of a causal chain physical (or even scientific)?

Hume's Problem of Induction already points at causation as suspect. We have continuous symmetries under transformation in physics, and they give us false confidence in the idea the simple principles can account for regularities in change. As you say, mathematics is a whole area of logical rather than causal relationships.

In modern physics, in order to find a theory of quantum gravity, it is widely expected that space and time will be emergent. Such as in Loop Quantum Gravity. The Holographic Principle can help give insight into how this might work, with a way of talking that sees a surface between objects, then something like the AdS-CFT correspondence linking a surface to a way of talking that looks like a 'bulk'; but actually they are different ways of talking about the same thing.

  • I am going to accept this answer, but you bringing up the post about causation does make me wonder more about deleting my question 😕 is my question different enough to merit keeping up? Nov 16, 2022 at 23:27
  • I'm also weirded out because I've found copies of some of my questions on other websites. Like one of my HistorySE posts was copied into some Russian site a while back. I don't know what's up with that and I don't want to post useless stuff that then seeps into weird corners of the Internet. Nov 16, 2022 at 23:41
  • 1
    @KristianBerry: I really wouldn't worry about it. If you struggled to find things related to your topic someone less familiar with the site would be bound to, so now they are more accessible. Part of the strength of SE is the visibility of answers on Google, & it contributing to a more informed world.
    – CriglCragl
    Nov 17, 2022 at 12:28

As Conifold helpfully explained here

McTaggart was an objective idealist, all subject bound constructs were "unreal" to him. ... He is asking for a tenseless explanation of tenses

McTaggart's B series is the tenseless 4D tesseract; a deterministic map of events, separate from living agency in which the present is perceived/reified. So there is no actual present in the tesseract. You can pick a time, any time.

In contrast there is the A series, where the present is the moment of living existence — the nunc stans — demarcating the tenses.

So is the notion of temporal determination, as A-series determination, required at all to interpret four-dimensionalism as such? Because it seems, here, not to be required at all.

There should still be considerations of entropy in a B series tesseract, so it is not a matter of indifference whether a chemical reaction, such as combustion, runs forwards or backwards. However the tesseract map/model is indifferent to tenses; it is meaningless to say the reaction has happened, is happening or will happen.

So in the 4D tesseract there is "temporal determination" in regard to the arrow of time, but not in regard to tenses.


One way to deal with this is to replace the notions of "cause and effect" with the notion of pattern. There are clearly patterns in the world. All cats have certain characteristics in common, for example. Apples are usually good to eat. All of the round, hard things you find in a streambed tend to be the sorts of things that you don't want to get hit in the head with.

This notion of patterns can be extended to patterns of events. There is a pattern associated with a stone flying through the air. It will continue to fly through the air in a mostly-predictable trajectory until it collides with something such as the ground or somebody's head. If it hits somebody's head, there is an additional pattern involving blood and skull fractures.

Rather than thinking of nature as a collection of causes and effects then, we can think of nature as a collection of patterns extended in time and space. This model of nature is fully compatible with scientific investigation, and is also compatible with a four dimensional view of spacetime.

  • Puts me in mind of Dennett's 'real patterns'
    – CriglCragl
    Nov 17, 2022 at 12:42

I cannot tell from your question whether your 4-d world is an imaginary concept or is intended to mean the actual spacetime we inhabit. If the former, then it will be subject to whatever rules you imagine. If the latter, then the concept of causal determination most definitely has a use- indeed, it underpins virtually every aspect of our understanding of reality.

There are certain dubious ideas baked into your question. You talk of the 4-d space being given in 'atemporal simultaneity'- I cannot quite fathom what you mean by that, especially since atemporal simultaneity seems to be an oxymoron of sorts. If you mean that it is possible to conceptualise the entire 4-d block without considering which 3-d surface within it might correspond to a particular 'present', then I agree with you, it is possible to think of it in that way in the abstract, but so what? It does not follow that the 4-d block has a material existence. Most branches of physics successfully model reality by assuming that all matter exists in the present. More specifically, if a particle exists at a location of spacetime with a time coordinate t (in whichever reference frame you wish), it does not exist at any point with a time coordinate of t plus or minus n, where n is any non-zero number you like. Particles are point like objects that move along worldlines in directions of increasing time- they are not 4-d shapes extending backwards and forwards through time. The equations of physics tell us how the configuration of matter and energy at time t will evolve with time, and we take that evolution to be causal, in the sense that interactions at one time lead to configurations at later times.

  • The SEP article on backwards causation says (sec. 4, "Physics"): "One has to remember that causality as such is an everyday notion that has no natural application in physics." Atemporal simultaneity is the classical (Boethian) definition of eternity, of "one eternal now." The notion is partly imported into 4-dimensionalism when it overlaps eternalism. Dec 13, 2022 at 13:13
  • The reference to tesseract- and circle-shaped worlds is just meant as a simplifying device, along the lines of ideal gas. Dec 13, 2022 at 13:15
  • Your quote from SEP is either utter nonsense or the SEP is using the word causality in such a specialised sense as to allow the sentence to have almost any meaning the author wishes. The Boethian definition is equally meaningless. Dec 13, 2022 at 22:20
  • How can you expect me to believe you over the SEP and other established analysts? In fact, if you understand how dimensional perception works (see e.g. Flatland), it's easy to understand that you would see all of a one-dimensional temporal manifold "simultaneously" if you occupied at least a two-dimensional temporal viewpoint, just as from our 3D spatial vantage we can see all facets of 2D manifolds "at once." This is just applied common knowledge. Dec 13, 2022 at 22:24
  • As a theoretical physicist, I take the view that there is such endless and inconclusive philosophical debate about time in part because the use of overblown language goes unchallenged. Dec 13, 2022 at 22:24

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