-2

This is a bit of a brain twister but it's a very serious question. Please be precise in your answer.

I do not believe time exists. I believe it is simply an illusion of our perception, the perception of seeing things around us change. The faster things change the more time seems to go by. In some sort, change is the result of the dissipation of energy. Thus what I believe is that what we are really observing is the energy being dissipated and created all around us and we call it time.

Since time doesn't exist (for me). That would mean that the equation of [ speed = distance / time ] is impossible. But nevertheless the concept of speed is fundamental for physics. What could we replace this equation with to no longer have speed dependent of time but of energy?

Qmechanic
  • 201,751
David
  • 47
  • 5
    If time doesn't exist, how long are you going to wait for an answer? – Phil Frost Aug 08 '14 at 10:55
  • 5
    What does the word to change or a phrase like being X mean if there is no time? – Tobias Brandt Aug 08 '14 at 10:55
  • 1
    The question is closely related to other questions, if not an exact duplicate, and it seems a clear enough question that has a clear answer. So I'm not sure why it's attracting so many downvotes. – John Rennie Aug 08 '14 at 11:15
  • 4
    @JohnRennie Although I did not downvote, I can imagine that OP's bold tone while defending a completely untenable position could be the cause of the downvotes. – Danu Aug 08 '14 at 12:01
  • It would help if you clarified whether this is a belief you hold personally or a postulate whose consequences you would like to explore. – Emilio Pisanty Aug 08 '14 at 13:10
  • @EmilioPisanty well it was both until John shook the belief, now it's more of a postulate I would like to explore. ;) But I'm not a physicist so there is only so much I know from highschool classes and online articles... – David Aug 08 '14 at 13:22
  • 1
    Julian Barbour's winning essay on the nature of time describes how classical mechanics can be viewed as timeless: http://www.fqxi.org/data/essay-contest-files/Barbour_The_Nature_of_Time.pdf Many other entries in the fqxi contest provide a lot of interesting ideas: http://www.fqxi.org/community/essay/winners/2008.1 – Void Sep 26 '14 at 22:55

2 Answers2

1

We know that to position objects in spacetime requires four coordinates e.g. $(t, x, y, z)$. So time certainly exists. The point you're addressing is about the flow of time. Incidentally this point is discussed in some detail in the question Is there a proof of existence of time?.

Any object traces out a worldline that is a curve in spacetime, and we can parameterise this curve by using an affine parameter $\tau$ that varies along the curve, then write the coordinates as a function of this parameter, $t(\tau)$, $x(\tau)$, $y(\tau)$ and $z(\tau)$. In fact this is exactly what is done in General Relativity. In GR the affine parameter is normally the proper time, but any parameter can be used and need not have any physical significance. For example photon world lines can be parameterised in this way even that the proper time is everywhere constant for a photon.

Having done this we can now calculate values for $dx/dt$, $dy/dt$, etc and even things like $dx/dy$ if we wish. Then we can define a coordinate velocity as:

$$ v^2 = \left( \frac{dx}{dt} \right)^2 + \left( \frac{dy}{dt} \right)^2 + \left( \frac{dz}{dt} \right)^2$$

So the point is that we can calculate a velocity without worrying about whether there is a flow of time in the sense humans normally use the term. There is no need to replace velocity with any other quantity.

Community
  • 1
John Rennie
  • 355,118
  • If there is no flow of time, how is $dx/dt$ defined? In other words: How do you derive the tangent of a function if you have only a single point? – pfnuesel Aug 08 '14 at 12:00
  • @pfnuesel: for any object there is a worldline spans ranges of $t$, so it is not the case that an object has only one value of $t$ that doesn't change. The flow of time is the claim that time moves forward along the curve. But the worldline is just a set of spacetime points and its existance does not imply motion along it. – John Rennie Aug 08 '14 at 12:36
  • @JohnRennie This is complex! haha but I really appreciate the answer. You blew my mind with your answer for Is there a proof of existence of time? (Genius) Still I wonder, does this mean that we could define velocity based on the fluctuation of energy but that it's not necessary? – David Aug 08 '14 at 12:43
  • @David: I can't think of any useful way to define velocity as a function of energy. Sorry! – John Rennie Aug 08 '14 at 12:44
  • @David: I would think that part of the problem in defining velocity in terms of energy is that energy is a scalar quantity (only magnitude) while velocity is a vector quantity (magnitude and direction). – Kyle Kanos Aug 08 '14 at 13:09
1

You could use the Length contraction equation of Special Relativity to determine speed. If you know the dimensions of an object at rest relative to you, you would know its velocity relative to you by finding which dimensions are length contracted and by how much when you measure the body in motion relative to you. But, full disclosure, I think time exists.

Chris Laforet
  • 2,467