Do we exist in the same dimension as time?

Question

For the past few week I’ve had conversations with many forums about this question that’s very pertinent to me. Is time fundamental just like space, or is it simply a property of the progressive nature of the physical universe?

Answer 1

Here is perhaps a simpler way to look at this.

Mathematically, the set of all real numbers exists on an infinitely-long number line, having only one dimension. The set of all imaginary numbers exists on another infinitely long number line which is positioned at a 90 degree angle to the real number line, and also having only one dimension. These two lines now define an infinite plane having two dimensions, which is populated by the complex numbers each of which contains one real number part and one imaginary number part.

Physicists mathematically map the time dimension onto a line which is at 90 degrees to the three dimensions of space by specifying that it is an imaginary number. That extra dimension is impossible for us to visualize because in 3-dimensional space, there is not any direction for a line to point in which is perpendicular to all three dimensions of space.

This means that the dimension of time is fundamentally different than the familiar three dimensions of space: you measure the length of time with a clock and the length of space with a tape measure.

We inhabit a universe which is mapped throughout by specifying four dimensions: 3 of space and one of time. To be "outside" of time would mean that time did not exist for you- there would be no past and no future for you. So time is woven into the structure of the universe, and the time dimension gets mixed up with the space dimensions when you are in motion relative to a point in this 4-dimensional space, according to Einstein's model of special relativity.

This means that time is just as real as space, but the book keeping rules you use to keep track of it are not the same as those you use for space- and in certain circumstances, they get blended together.

Answer 2

Being three-dimensional perceivers, we can see all sides of small enough two-dimensional shapes at once. Were we four-dimensional perceivers, we could see all sides of small enough three-dimensional shapes at once. Now, if time is not separable from space except in the abstraction of reflection, and so if time is a fourth dimension, not so much of space only but spacetime, then the fullness of three-dimensional physical states in our universe is as facets of a four-dimensional structure. So we experience the procession of time due to rotation, either of those structures before our eyes (so that we see successive three-dimensional states), or of ourselves in "orbit around" the four-dimensional structures (again, so that we see different things as time "passes").

Subtly but pointedly, the concept of "imaginary" time, meaning time as coordinated under the effect of an imaginary number, makes it so that time is not four-dimensional in the sense of 4 being the correct reply to, "What is n for our n-dimensional space?" but the answer is more like 3 + i, so that there are four dimensions but not four n-dimensions. Still, the nature of imaginary numbers, or complex numbers moreover, is such that this exotic conception is not entirely far from the concept of 4 = n for n-dimensional spacetime as we know it (in other words, 3 + i is not so different from 3 + 1, if you think about it from a certain point of view).

One philosopher, Immanuel Kant, styled the imperative of time as the "fact" that time is the "form of the inner sense." Now by this, Kant did not mean our sense just of our own inner states. He meant our whole impression of objects having inner forms, of being internally unifiable/unified objects. That time is the form of our sense of these things goes along with the longstanding question of personal identity over time, and so more broadly of object permanence and stability over time. Moreover, because Kant equates time with part of the prelogical function of differentiating and identifying particulars, he makes it so elementary to his system that to reject or denigrate time so much would be to reject the prelogic at play, which Kant was not of a mind to do.

Now lastly, consider science in general inasmuch as it involves the performance of experiments. Suppose we were trying to set up an experiment to prove that time isn't real. (Note, however, that often when physicists say things like, "Time is an illusion," they might not mean such a statement strictly; so we are not denying that time might be illusory in some fashion, only that it cannot be illusory in the full sense of that term.) Yet in running the experiment, we will be subordinate to time in that we will have to have time to set up the experiment, to perform it, and then to analyze its results. So while performing the experiment to determine whether "time is real or unreal," we will depend on the conception/perception of time to do so, and I would be surprised to find that there was any way to show that time is fully unreal, in such a context, using such a method. So if time is an inescapable presupposition of the experimental method, then there's nothing science can do to prove that time is completely illusory/delusive, and time's reality is otherwise guaranteed to us.

For all that, the question of whether time is more like a substance with properties (or a mass term over a type of substantial, propertied object), or more like a property of substances, seems partly answerable, in an evidentialistically justifiable way, in both directions: as if there is a timelike substance and a timelike relationality. As a substance, time is there independently/above changes in time; as a relation, time is encoded into the "flow" (activity^&&&) of time (the abovewards object) itself.

Or so one might say. I don't know that there's a settled meaning to all of the above questions, much less a settled conclusion of analysis of these questions.

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^&&&That is, it is not that time is like the water in a river, "flowing down the river." Time is an active presence; it is what is moving things "down the river," by acting on them. Granted, when we think of things besides the water in a river, flowing down the river, we think of the water as carrying them along; so as it turns out, we can still make an analogy between the passage of time and the water in a river. But we see time as more elementary than the river's water, we see time's action as more compelling than the action of the water in the river.

Answer 3

This is specifically in answer to the question: "Do we exist in the same dimension as time?"

In the following quote from Heidegger's Being and Time H.376-377, the primordial, authentic temporality of Dasein—that is, the play of time in instinct, thought and planning with the application of experience—is differentiated from ordinary temporality—clock-time, physical time. To whatever extent this is, to a degree, metaphorical, nevertheless this is a view that being authentically exists in a different dimension to the ordinary understanding of time.

Dasein must also be called 'temporal' in the sense of Being 'in time'. Even without a developed historiology, factical Dasein [factical as 'thrown', passive, reflexive—my comment] needs and uses a calendar and a clock. Whatever may happen 'to Dasein', it experiences it as happening 'in time'. In the same way, the processes of Nature, whether living or lifeless, are encountered 'in time'. They are within-time. So while our analysis of how the 'time' of within-time-ness has its source in temporality will be deferred until the next chapter, it would be easy to put this before our discussion of the connection between historicality and temporality. The historical is ordinarily characterized with the help of the time of within-time-ness. But if this ordinary characterization is to be stripped of its seeming self-evidence and exclusiveness, historicality must first be 'deduced' purely in terms of Dasein's primordial temporality (my emphasis); this is demanded even by the way these are 'objectively' connected. Since, however, time as within-time-ness also 'stems' from the temporality of Dasein, historicality and within-time-ness turn out to be equiprimordial.

Answer 4

Dimensions need not be correlated with what we humans comprehend in material reality with our senses. Dimensions in mathematical sense is a way of representation. The idea of space has its origins in human mind observing space around us, so that's why it started as 3D space and later extended to multiple dimensions. So it began as way in which human mind can comprehend abstract mathematical concepts to a representation that became abstract in itself.

Having said this, lets explore what is time. The right perspective from existing explorations done would be - time can be considered as an indication of the tendency of matter to gravitate towards a state which is of higher complexity (entropy). So time is a construct of human mind to comprehend the flow of events that arises out of this tendency of matter. And since dimensions were first understood with space that we are familiar with. When someone says time is fourth dimension, listener gets confused as they try to incorporate this with the notion of space that they are familiar with.

Dimension is just a construct used to represent mathematical entities in mathematical world. If you have to represent time (which exists in material world) in mathematical world you have to include that as a dimension since it is one of the variables in defining a state.

So mathematically Yes, we always exist in the same dimension as time

Answer 5

How convenient that I've literally just written up a YouTube comment that answers this exact question. What a coincidence. Anyway, here is my comment. Take it with a bit of a grain of salt as I'm not a qualified physicist, but I'm pretty confident my understanding is decently close to reality:

To me, it's pretty clear that spacetime from relativity is simply a 4-dimensional fabric that covers the 3 spatial dimensions and time. However, time in itself isn't a dimension, nor could it possibly be ─ time is simply the rate of change in the universe; of course, the concept of negative change is nonsensical ─ reverse change would still just be another form of change. It's for this reason that time, when treated as a dimension, has some very unusual properties, such as objects being unable to move in any direction but forward in it and objects not being able to have any size in it: it's all just because time isn't a dimension.

Even if the element of the spacetime 4-vector that covers time, which is an actual dimension, were to have a negative value, that still wouldn't have any effect on time itself, as objects simply can't move backwards through time. It would be the equivalent of trying to put a leashed dog on a treadmill ─ the treadmill would just move under the dog, but the dog would remain stationary.

By the way, time isn't the only non-dimension in relativity that is covered by a dimensional fabric. Spacetime curvature is another one. Ever heard of the concept of "shape of the universe"? Yeah, that's what it's referring to. The universe has no physical 4th dimension to have a shape in, but it, and everything in it, behaves as if it does. In fact, gravity itself is simply the extent of the curvature of the spacetime fabric in this nonexistent fourth dimension.

So yeah, this question is simpler than it seems. There is no mystery in time being unique among the other dimensions, because it isn't a dimension, nor is there any intrigue in the speculation of what it would be like if time was like the other dimensions, because that would simply be conceptually impossible (in the same way that 2+2=5 is conceptually impossible).

Answer 6

There are three common models for time, and they give very different answers to your question. They all also all have apparent refutations, so -- welcome to philosophy!!!!

The most common model for most of history was to treat time as just a convenient metric to refer to sequential state changes. This is often called the "A" model of time, or Presentism in philosophy. In this model, "time" doesn't really exist -- it is an invented concept by us to refer to the history of state sequences, and to project future state sequences. The only things that actually exist are the things of the universe, and they only exist in their "present" state -- hence "presentism". Under presentism, there is no "dimension of time", and time does not really exist, so no, time would not be in a dimension with us.

The more common model among physicists today is Block time, or the "B" model of time. This model treats time as a dimension of a 4-D Space-time continuum. This is Einstein's model behind General Relativity. In Block Time -- the past, present, and future all have the same status -- there is no special feature to the present. And the future is already set. Under Block Time, time IS a dimension. So no, it would not "exist" with us, in another dimension.

A third model is Growing Time -- which treats the PAST as in Block time, but the future does not yet exist. The present has a special status as the edge of Growing Time. Growing time was developed as a "fusion" model -- an effort to find a way to incorporate the best features of Block time and presentism in a better model. In Growing Time, time only exists in the past, but not the present or the future. But time would BE a dimension in the past, not "in" a dimension. So once more, no we would not be in the same dimension.

Eah of these models is useful for different purposes. Block time is super useful for a lot of engineering and physics problem solving. Presentism is useful for evaluating causation, and logic questions. Growing time for anything involving history or retrospection.

But each of these models also has flaws:

Block time provides no explanation of our sense of the present -- a theory of time which fails to predict or usefully understand the primary feature of time -- is a remarkably weak "theory".

Block time advocates generally assert that our experience of time is an illusion, and call for us to dismiss primary experience in favor of theory -- which is explicitly anti-scientific.

Block time is also in conflict with all indeterministic models of Quantum Mechanics (which is most, or arguably all of them).

Presentism appears to be in conflict with the process aspect of physics, in which all events and interactions have duration. An infinitesimal approach to time's extent -- cannot usefully address how our universe seems to be coupled into longer periods than an instant. This problem is referred to as the "thickness" of the present.

Growing time gives the present a special status, addressing one flaw of Block time, but in growing time the present is absolutely SECONDARY to the past. But we don't seem to be able to interact with the past -- and the present seems to be far far more important than the past -- so a model that declared the inaccessible past to be "real", and the present is special in only a minor derivative way -- is still not a particularly useful model, and it too is contradicted by immediate experience.

Growing time also does not address the "thickness" problem for an instantaneous present -- the past/future boundary in Growing Time cannot have dimension or "thickness".

However, given that each model has falsifications of it, another possible answer is -- we don't have a good model, so we don't know how to answer your question.

Answer 7

According to relativity, yes, time is a dimension. (By the way, imaginary time is deprecated. You can limp along with it in special relativity, but it becomes very annoying in general relativity. People who work in gravity theory don't tend to use it.)

But let's creep up on it a little.

You experience directly a particular form of time. One name for this is affine time. You can experience such things as before and after, coincidental, longer and shorter, and similar properties. But you cannot directly measure time's duration, at least not with any accuracy. Students of geometry will refer to this as not having a metric for time. Here "metric" is a technical term for a geometric structure that lets you calculate the distance (or duration) between points in the geometry. Affine geometry does not have it. (Or it has it but we ignore it. Or don't have access to it.)

You can experience this because of one of the fundamental characteristics of identity: Sometimes you all go away but I'm always right here.

So you can experience before and after. Fred arrived and then Bill.

You can experience coincidental. Fred and Bill arrived at so close to the same time you cannot distinguish.

You can experience longer and shorter. Fred arrived and then Bill. Then later, Bill left, then Fred left. So Fred was here longer than Bill.

Using these you can build up a quite complicated network of events. This event happened before that one. This set of events is continuous and extends before and after that one. And so on. In particular, you can establish relationships such as "is at rest with respect to another thing." (As long as we stay in a flat geometry, and so in special relativity. It gets much more complicated in general relativity with a non-flat geometry, but the ideas remain.) This is because you can establish that the distance is not changing, even if you cannot determine that it is any particular value. This is because you can establish longer or shorter.

But we cannot accurately measure duration without some type of device. Usually this is referred to as a clock. Our direct experience of space is similar. Left-of, longer than, and so on, are available. But accurately indicating how long a set of points is requires a device. Usually there will be diagrams with some kind of measuring ruler or some such.

Of course, allowing in a device of this kind means we have to accept the use of devices. And that brings in a whole host of assumptions and notions about reality, the acceptability of observations, repeatability, etc. and etc. Those are all suitable philosophical topics, but this post is already overly long.

In relativity a clock is a device that marks time in physical units. You are familiar with a variety of clocks that mark seconds, minutes, hours, etc. In relativity, clocks take on a particular aspect of importance.

Both clocks and rulers are methods to establish a relationship with a measurement standard. Performing a measurement means to determine the ratio between the standard and the measured interval. So many seconds or so many meters. A clock or a ruler must be able to accomplish this to function correctly.

So what do we find in relativity? Let's stay with special relativity for now. It's hard enough and this place does $not enable$ equations.

What we find is, if one observer builds the affine network mentioned, he will think that event E1 comes before event E2.

But another observer, B, (specifically one moving with respect to A) will construct a different affine network. And he will think that event E1 comes after event E2. (They will also disagree about relative locations of events, but you asked about time.) If you want more of the technical explanation, the wiki article is not too terrible.

What does this imply? Different observers will disagree about the time-ordering of events. One will say Fred arrived first, the other Bill.

And the crucial part of this is, this impacts on the affine time level of experience. We don't need to measure any duration to note that the two disagree about ordering. All of the observations required are direct. It is not necessary to have a clock or a ruler to observe the ordering of events. And this directly observed thing changes.

This is because space and time are part of one geometry. And a change of velocity has some of the same types of property as does a rotation in ordinary 3-dimensional space. (Some, but not all, of course.)

Consider a trivial example. Fred has a ladder. When standing straight up, the ladder is longer than Fred is tall. Now Bill takes that ladder and leans it over against a wall. Earlier Fred and Bill stood back-to-back to compare their height and were the same. But now, with the ladder leaning against the wall, its top is lower than Bill is tall.

Notice that the same effect could be achieved if all we had was Fred, Bill, and the ladder, and we rotated Bill instead of the ladder. This "getting the same thing" is at the heart of relativity theory. A rotated Bill sees the ladder shorter along his length. A non-rotated Bill sees a rotated ladder the same way.

A rotation of a physical object changes its projection onto the vertical dimension. It also changes its projection onto other dimensions, but in particular, it changes the vertical part. So a leaning ladder is not as tall. This is because the three space dimensions can be rotated into each other. The space-ordering of locations can be changed by such a rotation. The top of the ladder if above Fred when at Fred's angle, and below Bill's head when at Bill's angle.

A qualitatively similar thing happens with space and time. By setting one observer moving relative to the other, their projections of events onto the time coordinate will differ. A moving ladder is, in a manner of speaking, leaning over. So the time coordinate appears fore-shortened. (As does the space coordinate.)

Thus: Time is a dimension. It has many of the same properties as the three space dimensions. It fits into a single geometry called space-time. It can be "rotated" into the space dimension by a change in velocity.