When someone says that they have no time to plan, we usually interpret this as the claim that they have a busy schedule and they cannot find a spare moment in which to sit down and plan for the future. There’s all sorts of fairly obvious reasons why that’s a bad thing. But here’s a startling claim: none of us have any time to plan, because it turns out that there is no time.
What, you might wonder, could that mean? It’s a claim that a number of modern physicists are making and if it’s true it surely radically alters the way that we see the world and ourselves in it. That’s not to suggest that there aren’t fairly trivial assertions we might make about there being no time in our world. For centuries philosophers have made what seem to be radical claims about our world, but which on reflection sometimes turn out not to be so radical. For instance, some philosophers have thought that it is an essential feature of the nature of time that events in time have both an ordering and a direction, and others have thought that in addition to that, there must be a privileged location in time which is “the present” moment. But modern physical theories cast doubt on both of these claims. So if any or all of these features are essential to time then, the thought goes, there isn’t any time.
That sense in which there is no time does not look like anything the average person needs to worry about. For it seems open to any of us to simply resist the claim that any of those features are, in fact, essential to time. Instead we should surely conclude that the temporal dimension is somewhat different to what we might have thought. None of this gives us any reason to conclude that we do not remember events which are, relative to us, in our past, and that we should not plan for events that will be, relative to us, in our future.
But that is not the full story. Some physicists have toyed with the idea not just that time might be different to how we suppose it to be, but that there is no good sense to be made of the idea that there is a temporal dimension at all. The idea is that perhaps there is no unique set of three-dimensional “time-slices” that make up our world, and which can be ordered into a unique correct ordering.
Think of our world as being like a deck of cards. Imagine each card is wafer thin: it has no width at all. So each card is two dimensional, and the whole pack is three-dimensional. Now suppose instead that the whole pack has four dimensions, and that each card therefore has only three dimensions. So each card is like the whole world at an instant in time. It has no temporal duration, but has three spatial dimensions. We generally assume that there is one right way to order these cards, from earliest to latest. The card the features the moment of your birth, is before the card that features the moment of your death.
When Einstein came along and presented the theory of special relativity, he effectively suggested that there are many equally good ways of “slicing up” the deck of cards. The deck we are imagining is composed of cards, each of which has a number and a suite on it. Imagine we stick the cards together (and thus stick them together in some order or other). We can then take a sharp knife and start slicing the deck up into a new set of cards. If we slice the deck at a angle, then the cards the we get, at the end of the slicing process, are different to the cards we stuck together: they have different combinations of numbers and suites on them. We are effectively cutting across the original cards that we stuck together, so each new card has components of a number of our original cards. There are, of course, any number of different ways of slicing up our deck. Each way of slicing represents the fact that according to the theory of special relativity, from the perspective of different frames of reference different events count as being simultaneous. That is, depending on which way you slice the deck, you get different things (events in our world, numbers and suites on a deck) on the slices, and each slice represents a single moment of time. So depending how you slice the deck, different events count as being on the same slice, versus on different slices (count as being simultaneous, or not simultaneous).
This being said though, it still turns out that there is one right way that all of the slices go together to form a four-dimensional whole. It’s just that there is no one right way of slicing up that whole. So there is no suggestion that time itself disappears.
More recently, however, there has been a suggestion that there isn’t even a right way of putting the cards together to form a four-dimensional whole. Instead, keeping the analogy going, the thought is that our world is like a deck of cards, but it’s a deck of cards that can be put together any way you like (as it were). Any ordering of the cards is as good as any other because the cards that make up our world aren’t really ordered at all. Some physicists suggest that the fact that our world seems to have an ordering is just the product of the fact that we seem to remember certain events, and the slice of the universe on which we find ourselves appears to have records of previous times: historical documents, fossils, and so forth. But these are all mere appearances, since there is no sense in which there are slices of the world that did exist in the past, and which are causally responsible for what seem to be memories and fossils.
If our world really is like this, then it seems plausible to conclude that there is no time. For in order for there to be time, there seems to have to be some sort of ordering of the events in the world. But if there is no sense in which other slices of the universe came before this one, and still further slices will come after this one, then one might well ask oneself what sense can be made of the idea that we are responsible for things that did happen in the past, and that we should plan for what will happen in the future. Indeed, the very idea of ourselves as agents in the world seems to require that the things I do now have down-stream causal consequences – that is, that they effect what happens in the future. If the slices that make up our world are unordered, it is difficult to see how to make sense of some of this notion.
It is still controversial what the right physical account is of our world, and hence controversial whether anything like this is the right picture. But it is worth considering just how important we take a phenomenon like time to be in our way of thinking about ourselves and the world. We experience the world as ordered, and almost all of our actions in the world are based on the supposition that the states of the world are ordered. It is worth giving pause to consider what we might make of our world and ourselves if that turned out not to be the case.