Agreed. It’s even hard to come up with a definition for time itself without using time-dependent words (”event”, “rate”, “succession”, and so on).

The power of science (and the mathematics used to describe it) is that it can tell us things that are true that are not only counterintuitive, but nigh-impossible to imagine.

Actually, it’s an expansion of space, not of space-time.

Ah, thanks! I haven’t studied GR, but here is the FLRW metric of the concordance model, with a spatial scale factor. Mea culpa.

@ MattFunke:

I have no idea who started it, but it sure gets trotted out an awful lot.

I thought it was Hawking, on his “no boundary condition” cosmologies? There is definitely no initial “time” with such an absence of proper boundary.

Except for the conceptual problem of what spacetime is expanding into. This is a problem generated by our brain’s formulation for dealing with a cause/effect and time dependent scale of being. It is impossible for most people to conceive of how something can be expanding without expanding into something.

Barton Paul Levenson said:
> Are you aware that the tensor equations governing the standard model of the Big Bang have both space-time and mass-energy being created at T = 0, which implies that nothing existed before the Big Bang? That saying something existed before the Big Bang is therefore like saying something is north of the North Pole?

You are equating the lack of time and space with nothing. I think this again one of those conceptual problems. We are stuck thinking of before and after, so there must be a before time began. I’m not certain if the problem is our need to have a before t=0 or our inability to make sense of the idea there could be something before/beyond/outside of “space”, i.e. our current universe.

> Actually, it’s an expansion of space, not of space-time.

Except time is just another “dimension” equivalent to the 3 space dimensions in many ways. Thus GR combines the 4 items into one linked article. That’s the root of all the inconstant time issues of GR.

MattFunke said:
> That’s why I was trying to distinguish between “past for all time” and “eternity past”

You’re being hampered by our language deficiencies that arise from our conceptual limitations. “Before” and “eternity” are inherently time concepts. It’s a definite conceptual paradox.

You have to make someone actually want to learn, and that involves convincing them to exercise some independent solid intellectual fortitude.

I won’t be holding my breath.

“I was hoping to get Mike J. there with reason before whipping out the Math Bludgeon.”

THAT would have been downright bloody!

Funny. I’ve used that analogy myself. I have no idea who started it, but it sure gets trotted out an awful lot.

Here’s what I’m getting at, without having to appeal to tensor equations, and lacking the proper HTML tags to represent them in any event: saying that something existed “for all time” means that it existed whenever there was time. That’s why I was trying to distinguish between “past for all time” and “eternity past” (as slippery a term as that might be) in my previous post. Note that “always” also refers to (as the American Heritage Dictionary of the English Language, 4th ed., puts it) “at all times; inavariably; at any time; in any event”.

Speaking of cause-effect relationships outside of time seems a bit nonsensical. Saying that something had to cause the Universe to exist begs the question of why we have to assume that there was a time when there was nothing. Since there was no time outside the Universe’s creation, of course, it’s not even reasonable to assume that such a time even existed.

I was hoping to get Mike J. there with reason before whipping out the Math Bludgeon.

[[Except that there is no spacetime for the universe to explode in, so people prefer to describe it it as an expansion of spacetime itself. (That takes care of the problem with the connection between space and time in relativity too.)]]

Actually, it’s an expansion of space, not of space-time.