Time is just a concept, and cannot exist by itself.

"Time, like space, is a necessary and a priori condition of existence. In the above quote, even you say that time is a necessary measure. Necessary = "absolutely essential; indispensable" (The American Heritage Dictionary, Third Ed.) So your words end up meaning that time, even if it were just a concept that we used to describe change, must exist. I will say that we do measure time in terms of change, and that our conceived increments of measurement (hours, minutes, etc) are rather arbitrary, but that time still does exist externally of us. I won't say that what is called "time" isn't a somewhat fuzzy area of our understanding, though." Indeed it is a necessary measurement, and your definition of "necessary" is accurate. However, the term "necessary" can apply to the existence of many things, not existence in general. I can argue that the eye is necessary to see, but the act of seeing is not in and of itself necessary. I can argue that "time" as a concept is necessary for the development of human understanding of physical laws, but this does not automatically imply that time must exist in order for the universe to exist. Thus, whether or not the CONCEPT of time is necessary has nothing to do with whether TIME IN AND OF ITSELF exists. "The concept of change, I believe, is just a result of human thinking. Upon forming beliefs on how things are, what they are, what they do, and what they should do, we define change. Thus, we see time as a necessary 4th dimension and do not question its existence." "All concepts are the result of human thinking. We conceptualize the three spatial dimensions and give them the name "space" because we perceive them directly at all times; why and how is the concept of time any different? It has different properties than the spatial dimensions to be certain, but this does not invalidate the idea of time as a dimension in any way. Space and time complement each other, one could say." Yes, but are these three dimensions actually three separate dimensions? Or is the separation of space in general into length, width, and depth purely due to flaws in our observation? If all motion ceased, things would both exist and exist in a particular place. However, there would be no measure of time. Thus, our concepts of mass and space are on a different level from our concept of time. We draw the concepts of mass and space directly from our senses. Our concept of time must go through several assumptions first, namely, associating motion with change. "I do understand what you meant by "we see time," but for the sake of being technical, and for the purpose of understanding my position, I would say that we "see" the spatial dimensions and that we more or less sense the temporal dimension internally. Could you expand on the second sentence in that paragraph, please?" Yes, as it is just a more in depth explanation of my reasoning in the explanation preceding this one. Bacteria and other single celled organisms do not have free will. Their actions are monitored purely by chemical response. More importantly, bacteria and other single celled organisms cannot sense time and I attribute this to not being able to form opinions on how things should be and comparing it to how things are. This is the basis for the concept of motion and translating it into change. It is also the basis for the concept of time. However, bacteria are able to sense mass and space, as they are made up of matter and interact with matter accordingly. Humans sense time in this way: First, they recognize mass and space inherently. They then begin to make assumptions and allow their bias to take over. They see a difference between a moving object and a stationary object, even though objectively, all things are moving. An infant seeing a mobile rotate in a stationary room would be able to form opinions on motion and change. Mobiles can stop moving, and when mommy pushes it, it moves again. The concept of time is derived from these human traits of combining these assumptions. More in the next response. "There is human bias in everything we do because all experience is subjective. However, there would continue to be both time and change even if humans, or any other form of being, did not exist to sense it and make their arbitrary divisions and measurements. It might be likened to the old (and perhaps trite) philosophical question, "Does a tree make a noise if it falls in the woods and no one is around to hear it?"" This goes with your below point about arbitrary naming. The word "sound" is actually referring to air being vibrated from the force of the mass of the tree interacting with the mass of the earth. If there were no humans or other animals around with the correct instrument (ears) to interpret that vibration of air, it does not make a "sound" as we know it. Rather, it makes a "sound" in the sense that a precise physical reaction has taken place. More in the next response, your argument flows very well. "Similarly, humans weren't always around to perceive time and change, but things changed nonetheless, and the clock was running, so to speak. I would also like to add that the passing of time is "felt" by all life, not humans exclusively. It is only homo sapiens that gave the process its name, after all of the evolutionary changes that had to take place for us to have the capacities (especially language) to do so. Change is not an illusion, and it takes time to change, therefore time exists." I have also struggled with this point before. The way I reason it is this: If all motion in the universe ceased, then began again, would we be able to tell how much time passed? My answer would be, no. Anything we use to tell time operates exclusively with space and mass and completely relies on comparison to other things. If all motion were to stop (every atom in the universe ceases motion, every subatomic particle) then there would be no objective measure of time. We would not be able to use the movement of the stars (which would stop too). Our "biological clocks" would not keep running because the chemical reactions that allow it to run would have halted. Neurotransmitters would have halted between neurons at the synapse. It would be completely impossible to say how long motion stopped for. In essence, when all motion or change stops, time effectively stops. So no, time is not a basis for motion or for change. There is nothing objectively supporting the existence of time. This is why I conclude time to be nothing but a concept.