When you look at the psychics of it, many scientists believe that the temporal dimension is the fourth. But the problem I see with this now is it does not correlate to the first 3 and it should, or be termed or defined as something else.
I’ll explain why. In physics spatial dimensions have a classical theory describing three physical dimensions: the basic directions in which we can move are up/down, left/right, and forward/backward. Movement in any other direction can be expressed in terms of just these three. In its simplest form: a line describes one dimension, a plane describes two dimensions, and a cube describes three dimensions.
Example Co-ordinate Systems:
Small excerpt from Merriam-Webster Dictionary
Noun- Measured or measurable period. More broadly, it is a continuum that lacks spatial dimensions. Philosophers have sought an understanding of time by focusing on the broad questions of the relation between time and the physical world and the relation between time and consciousness. Those who adopt an absolutist theory of time regard it as a kind of container within which the universe exists and change takes place, and believe that its existence and properties are independent of the physical universe. According to the rival relationist theory, time is nothing over and above change in the physical universe. Largely because of Albert Einstein, it is now held that time cannot be treated in isolation from space (see space-time). Some argue that Einstein's theories of relativity vindicate relationist theories, others that they vindicate the absolutist theory. The primary issue concerning the relation between time and consciousness is the extent, if any, to which time or aspects of time depend on the existence of conscious beings. Events in time are normally thought of in terms of notions of past, present, and future, which some philosophers treat as mind-dependent; others believe that time is independent of perception and hold that past, present, and future are objective features of the world.
But the point is, a temporal dimension is the measurement of a non-spatial element and is one way to measure physical change. It is perceived differently from the three spatial dimensions in that there is only one of it, and that we cannot move freely in time but subjectively move in one direction.
Because of these exact constraints, I believe describing time as a ‘dimension’ is not correct. Time is merely a bi-product of the first 3 Dimensions.
The equations used in physics to model reality do not treat time in the same way that humans commonly perceive it.
Their models, perceive time flowing in one direction is an artifact of the laws of thermodynamics. The best-known treatment of time as a dimension is Poincaré and Einstein's special relativity and general relativity, which treats perceived space and time as components of a four-dimensional manifold, known as spacetime, and in the special, flat case as Minkowski space.
So is the Temporal Dimension the 4th Dimension? I don’t think so. I think it needs its own classification. Dimensions should be spatial measurement only. To clarify, parallel dimensions probably have measurable spatial features, I think it is safe to classify them in with dimensions as well. Even the Astral Realm I would consider as a dimension, but Time...?
I use dimensions heavily in my next book because the character Kealin becomes trapped in one different from where she belongs.
I know it seems like such a nit-picky thing to debate with myself, plus the guy I had lunch with ages ago doesn’t even know the debate is still going on in my head. What a wack-a-doodle I am.