What would it mean for time not to be real?

Question

According to Kant, time is a pure intuition, meaning (in part) that its existence depends on the nature of human cognition. According to this doctrine, Other beings could in principle not experience time though they live in our universe. There are other accounts of time as well which attack the idea of time as an independent physical reality and make it something else. I find that I am unable even to grasp what it would mean for these sorts of things to be true.

It's not the same with space. Space is another pure intuition according to Kant, and in the case of space, I believe I can at least grasp the concept that space is just how humans intuit the relationships between objects. Other sorts of beings might have very different intuitions of space. Imagine, for example, a blind creature who lives in water and can't swim but can only crawl along the bottom. Such a being might detect objects through sound. What we see as distance, this being hears as volume. Horizontal angle might correspond to what we hear as differences in tone such as the difference in tone between a guitar and a saxophone playing the same notes. Distance above the surface might be represented by pitch. This being could understand position and motion as a theater of sound, having no sense of space as we understand it.

However, the creature would have to have a sense of time similar to ours. It has to recognize that events happen in order, and that there is no going back to a previous event. And the creature would have to have a sense that there are future events that must be prepared for (such as the approach of a predator). How else could it interact with the world? Or, taking seriously the notion that time is a pure intuition, how else could the creature interact with the temporal universe that humans experience in a way that is rational and leads to survival?

The notion of a sequence of events that plods on incessantly, with no possibility of going back or stopping or hurrying forward, and with the need to react to what is coming in the future, based on what is learned from what happened in the past--that's what time is. How could any creature exist in our universe without sensing that in roughly the same way we do?

Answer 1

'Time is not real' should be understood not as the claim that you do not experience time, but rather time is constructed by our brains and is not strictly speaking physical.

From the SEP article Time:

In a famous paper published in 1908, J.M.E. McTaggart argued that there is in fact no such thing as time, and that the appearance of a temporal order to the world is a mere appearance. Other philosophers before and since (including, especially, F.H. Bradley) have argued for the same conclusion.

Going back to the Hobbesian notion that change is motion (PhilSE), and as the user SystemTheory has noted, time is a shorthand for motion. A year is the motion of the earth about the sun. A day is the shorthand for the motion of the earth spinning relative to the sun. An hour is 24th of a day, and so on. Consider what seems so revolutionary when you first learn it, that time is relative to a frame of reference, really isn't. Time dilation is non-Netwonian because of the metaphysics that says the speed of light impacts our experience of clocks. You cannot smell time. You cannot feel time. You cannot weigh time or put it in a container. You can simply experience it by noting change. 'Time' in the abstract, simply is experience generalized over concrete experiences of definitive periods of time. The next best definition are the circular definitions of time, velocity, and motion, each defined in terms of the other.

Dennett is his book Consciousness Explained has a chapter devoted to the psychology of time which is much more contemporaneous and scientific than Kantian language. On page 144, in the chapter Time and Experience, Section 2. How the Brain Represents Time, he goes out to map how the brain functions in architectural terms and makes a simple argument. Time is a type of non-sensory neural calculation that is used to help sequence bodily events. As such, the building blocks of consciousness, events, are nothing more than a collection of events which are themselves delimited by two unique events: one of which marks the beginning and one which marks the end creatively delimiting events recursively temporal content.

Time as a construct of the mind is a concept supported by the framework of embodied cognition (SEP). The basic premise of embodied cognition is that the products of the mind, that is mentality and to a wider degree philosophical intentionality are directly grounded in, shaped, and constrained by the nature of the body that produces the mind. (Yes, there's a metaphysical presumption about the relationship between mind and brain.) In fact, it is a central contention of embodied cognition that mind is understood much more broadly than mere brain activity, but includes the body itself supported by such hypotheses as the somatic marker hypothesis and provides a foundation that cognition itself might be understood as extended or social in nature.

Given that we are born with naive realism as our fundamental cognitive strategy for organizing our mental activities, it is important to reflect on 'real' as understood through the lens of broader meta-ontological commitments. If your notion of 'real' is tied up in empirical claims, then it might sound nonsensical to declare time imaginary if imaginary is used as a synonym for bogus, illusory, or not accessible to the public. You invoke the term reality, but to a conceptualist like McDowell, it is important to differentiate among physical, perceptual, conceptual, and social forms of reality.

Classic physics notions like time, space, and energy aren't sensible. They are instead intuitive faculties that allow our consciousness to emerge and persist. They are not directly available to our senses, but rather allow our senses to come into being. This is what makes Kant's project of marrying Newton to Leibniz so fruitful. The recognition that time like space are intuitions that inhere to the mind helps us to understand the role intuition plays in framing our conscious experience and reframing the conversation in a layered model of reality leading from the noumenological with its pervading ontological ambiguity through the mysteries of qualia right to understanding the role language plays in shaping our concepts.

What about 'real time'? Doesn't time have to exist external to our thoughts? Well, that's not so clear. When talking about any form of reality, we are dealing with our thoughts about what reality is. If I make the claim 'time is real', reality itself is our model of the external world, and that model or any model of the universe is itself inescapably grounded in thought. This may be why the Wikipedia article on time says:

Defining time in a manner applicable to all fields without circularity has consistently eluded scholars.

Is human-like intelligence predicated upon this basic architectural feature of the embodied mind to create temporal content to augment mental representations for the purpose of sequencing and coordinating among the disparate parts of the body and keeping the sensory percepts organized? I would speculate yes. In much the same way that computer architecture has to have common features to embody physical computation, so too I suspect does language use and logical consequence depend fully on the same sorts of bodies that we broadly call animals.

For more information, see:

Time (SEP)
The Experience and Perception of Time (SEP)

Answer 2

Ok so you need two things. How we think about the function of dimensions. And our sensorium gets composed into experiences of the world, outside of our conscious awareness.

In this answer I relate our mathematical intuitions, to shared experiences of continuous symmetries: The Unreasonable Ineffectiveness of Mathematics in most sciences Consider time-crystals as an analogue to patterns in spatial arrangement, that generate properties. You can also look at Does light experience time? to understand how experiencing time is not necessary to have impacts on the world, but, it is required in order to travel below the speed of light, and have a rest mass.

This answer covers how the forward direction of time can be understood as the spreading out of information: How does entropy explain consciousness and the forward direction of time? Almost all fundamental physics is time-reversible, except a few CPT invariant processes involving the weak force, like beta decay, and these are thought to created the matter-antimatter assymetry in the universe. So know the ordinary processes of our biology could literally run backwards. What would that feel like? Information (quantum correlations) would get more concentrated - and that would relate taking away memory, instead of adding it. So maybe we can go backwards in time, we just can't remember it, and our subjective experience stitches together experiences in time order, only because our memory requires it.

Loop Quantum Gravity has a picture of emergent time, from a spin-lattice network. Carlo Rovelli describes events as like they are surrounded by a crowd of probabilities, and the timeline picks from them to move onward. The probabilities existence have real physical consequences, like the Higgs Mechanism, and Renormalisation Groups.

Time can be related in terms of Noether's Theorem, to the continuous symmetry of conservation of information, the conjectured but not proven law, used in solving the blackhole information paradox and indicating the holographic principle.

Anil Seth is a particularly clear expounder of how our brains do substantial work on our sensory inputs, to structure the information we have coming in so as to be suited towards us acting, like in this TED talk: How Your Brain Hallucinates Your Conscious Reality. We catch sight of this when we see how blind people use the same visual cortex, to include a lot more stored and non-geometric information from all their other senses. We can also look at how how our brain hemisphere assymetries (see hemispherectomy), seem to be related to having two models of the world, one with a slight bias inwards, one outwards, sustaining a sense of an external world which we are a mind-body within - even though for physics there are just, events.

It's easy to think of causality as fundamental, as a clear intuition. The real-patterns of particle physics mislead us, that all causal units are so self-evident. When we really think about it, causality even of particles, is really only a kind of story-telling. Discussed here: Is the idea of a causal chain physical (or even scientific)?

Imagine a being, with parts inside itself moving sufficiently quickly, that they would experience time dilation relative to each other. How would that being experience time? It would be a bundle of timelines with rythmic variations (what moves away would have to move back, if it's not fragmenting), not your intuition of one clear one.

Or consider by analogy with us observing a being in Flatland, how a being in higher dimensions than us would observe our own. Discussed here: Is it possible to visualize higher dimensional space? Even bound by time, they would have a radically different experience of events, seeing our timeline as just one surface in a volume containing all the branched possibilities.

Answer 3

The relationship of time to space has been known since the appearance of Special Relativity. The relativity of simultaneity means that if an observer observes a succession of events then another observer who is moving relative to the first may observe these as events laid out in both space and time.

Given that a sequence of events for one observer can appear as events spread out in space for another observer any questions about time also become questions about space. The question "does time exist?" is also asking "does space exist?".

For a given observer time is an independent direction for arranging events. A bit like space but it enters the metric of space-time with an opposite sign to that of spatial dimensions - see https://en.wikipedia.org/wiki/Spacetime.

Your question was about how we experience time. The experience of time is like the experience of space: how do we experience space? The experience of space, such as the background of this text, is a simultaneous set of events surrounding an apparent observation point. How is that done? Answer that question and you will answer the problem of space and time perception. The clue is in the word simultaneous. There is too much to explain further here, see https://drsimonrobin.substack.com/p/our-reality for many of the answers.

I have been asked to explain a bit further.

Notice in the top right graph in the illustration above that the x-axis of the moving observer crosses several events in the "stationary" observer. These events, which were successive for the stationary observer are simultaneous for the moving observer.

Suppose we have a line of events arranged in space. The physics of simultaneity tells us that these events could be successive events for another observer. The events which, in one frame are separated by time are separated by space in the frame of reference of the moving observer. They are the same events in both frames. What has happened is that there has been a rotation in four dimensional spacetime - a bit like things can rotate in 3D. (The rotation is possible because the 4 dimensions are part of the same 4D pseudo-Euclidean manifold. https://en.wikipedia.org/wiki/Manifold).

If spatial length can be interchanged with temporal length then we cannot simply wish time away. See https://en.wikibooks.org/wiki/Special_Relativity/Simultaneity,_time_dilation_and_length_contraction for a simple introduction to relativistic simultaneity.

This analysis tells us a great deal about physical time. Could we find an animal that did not know time or had a different time from physical time?

We can use clocks to show that we are not aware of any mental processes that take no time. Knowing is a mental process so knowing without time would be nigh impossible.

Processes occurring without time are not entirely impossible but they would entail components that are outside of spacetime - outside of both space and time because spacetime is a continuum. If we are allowed to stray outside of spacetime then the possibilities are unimaginably infinite so the original question would have no definite answer.

Answer 4

I think your intuition is self-evidently correct- animals must have some experience of time just as they must have some experience of space. So either Kant's claim was incorrect or perhaps he had something else in mind when he said that time was pure intuition- perhaps he did not meet that it was wholly a product of the human imagination. What I suspect, but cannot prove, humans do which animals do not is to speculate on the nature of time in a more abstract sense, and it is perhaps that aspect of time that Kant treats as the product of the human mind. Time and space exist in some sense, as they are indispensable to our understanding of the working of the Universe. Curvature of space and time explains why apples fall to the ground, and our best models of the Universe suggest that more than thirteen billion years of time elapsed well before there was a single human to imagine what it was.