demrald

This is a problem involving both philosophy and physics:

Hume's problem of induction aside (that is, assuming causality occurs at least in the universe as we know it), my understanding of physics is that the big bang is essentially a causeless event, as:

1) time is necessary for causality
2) time did not exist prior to the big bang

Is this assessment correct?

While the fact that the big bang was uncaused would not establish that God does not exist, it would make it possible for the universe to have come into existence at some point in the past without any divine intervention.

Mark_Chid

Time is simply the distance between events.

Space is the distance between things.

Thus you cannot have time without events or space without matter.

'Time' is not some thing or force that leads to causality, its just the way we measure the gaps between casuse and effect.

demrald

But am I correct in assuming that causality can't exist without time?

Mark_Chid

Thats like saying a tree can't exist without space

Its self evident, its a trivial statement.

'Time' is not a THING. It doesn't exist in and of itself, its a measurement of causality and events. Nothing is 'dependent' on time.

demrald

I thought the answer might be something like this, but my knowledge lies more in the realm of philosophy than physics, so I wanted verification from someone more informed in the field than I. Thanks.
Well, I wasn't trying to reify time, it's just difficult to discuss the issue without doing so linguistically.

tronvillain

Well, something analagous to time would seem to be required for causality, but it is not impossible that something analagous to time could have existed before the Big Bang. As a result, it is not certain that the Big Bang is an uncaused event, in the absence of any evidence for a "meta-time" or a "meta-universe" it seems to be a reasonable hypothesis.

demrald

I agree. I've just had theists throw "That violates the laws of thermodynamics!" in my face so many times on this issue that I thought I would seek some collaboration on the matter, as <a href="http://www.physics.org" target="_blank">www.physics.org</a> wasn't helping me much.

Ron Singh

When you say, "1) time is necessary for causality",

you have it backwards. Truly, it is,

"1) causality is what we call time".

Time is change.
Change is not contingent upon time; it is time.

NialScorva

I think you answered your own question when you referenced Hume's problem of induction (actually abduction). I don't have my reference handy, but Hume argued that the expectation of causality is a habit we form by repeatedly seeing things happen in sequence. Causality is the expectation that one thing follows another. The problem, of course, is that conventional notions of causality, like most "common-sense", only works in situations that are common. The beginning of the universe is anything but common.

Also, Hume argued that one cannot infer causality from a unique instance, which led into a scathing commentary on miracles, btw. For example, if we see A followed immediately by B, both of which are events we've never seen before, we have no way of determining if they're connected or not. It's quite possible that there was some unobserved event C that led to A and B, but A and B are not causally connected.

Yet another problem is that it's very difficult to go from the effect back to the cause. Even if the notion of causality applies, the big bang is an abnormal unique effect, thus putting it squarely into all 3 problem areas of causality.

Also don't forget that rules of causality tend to break down in some quantum situations. Particles pop into existence and decay into pieces for no reason, or at least it's proven that there's no knowable reason. The beginnings of the universe are thought to be a quantum event packing energies we have no means of predicting.

demrald

NialScorva

I agree, and thanks for your comments. I only mentioned Hume's problem of induction (or abduction, as you have said) to make clear that causality in normal circumstances was being assumed for the argument.