Bomb#20 said:
What, are physicists a type of demigod in your mind? They're regular human beings with a specialization, just like electricians. Some of them have thought about time and space more carefully than me, and some of them haven't.
I am not claiming that physicists are demigods. I am simply aware that time and space are part of their area of expertise because it is the very thing that they study, and here you are clearly claiming to know more about time and space than the experts who study time and space. While it is entirely possible that you are correct, perhaps you can understand why I find your claim highly unlikely.
First you would have to demonstrate an understanding of what physicists understand about time and space before you can claim to know more than some of them, and you have not as yet demonstrated that. You have simply made the
claim that you understand time and space better than some unspecified subgroup of physicists.
It is entirely possible that you know more about medicine than medical researchers, but if you want me to believe that is the case, then you're going to have to do something to demonstrate that this actually is the case. It is entirely possible that you know more about circuits than electrical engineers, but if you want me to believe you, you are going to have to demonstrate that this is actually the case.
You have made the claim that you understand time better than the people who study time (among other things) for a living, yet so far you have not demonstrated that you have any understanding at all of what the experts actually know or don't know about time. You simply declare your superior expertise and expect me to accept you at your word.
Let's back up a second here. Where the hell are you getting the notion that I expect you to accept me at my word? I was arguing with Random Person. You butted in with a pile of insulting nonsense. Whether you accept my expertise is immaterial because I am not offering an argument from authority. I explained why Random Person was wrong, and that explanation is equally solid whether it came from me, from Stephen Hawking or from a million monkeys at a million typewriters. (Oh, and I bloody well do know more about circuits than most electrical engineers. I'm a professional electrical engineer with a dozen-odd patents and a well-above-average EE salary, and it's no skin off my nose if you don't believe that.)
The second claim at issue here is unimportant and let's dispose of it quickly: the claim that I understand time and space better than some unspecified subgroup of physicists. That's not something I need anyone to believe; I only pointed it out because for some reason best known to yourself you chose to take for granted that it isn't the case and insulted me over it. You're talking as though it's an extraordinary claim. Why would you imagine such a thing? What, you seriously think
every single physicist understands time and space better than some random but competent EE?
That would be the extraordinary claim -- that's not the way human expertise is distributed. You might as well claim every single professional chef can make better stroganoff than my mother. There's a Gaussian distribution of understanding among physicists as among every other specialty;
of course some of them are going to be below me. If you've ever had a college physics class them some of them are probably below you -- that's Gaussian distributions for you. Moreover, you're wrong about what it is physicists do. No, time and space are not what physicists study, for the most part. The great bulk of what they study is the particles and waves that fly around in time and space. Einstein studied time and space; but the average working physicist takes time and space as a given and doesn't even use what Einstein found out about them. 90+ percent of quantum mechanics problems are solved non-relativistically, because it's a lot easier and the resulting inaccuracy is tiny. So no, here I am clearly not claiming to know more about time and space than the experts who study time and space; I'm claiming to know more about them than some subset of the experts who study band-gap energies and nuclear reactions and leave time and space to the Einsteins of the world. Clear?
Now, as to what I was actually claiming when you butted in. What is it you disagree with? That a time dimension and causality are two different things? Do you understand the difference between a "weak order" and a "partial order"? Look them up in Wikipedia if you don't. A time dimension puts a weak order on events. Causality puts a partial order on events. A partial order is a mathematically looser constraint on a relation than a weak order. Therefore causality doesn't logically require a time dimension. Therefore discovering that a time dimension has a beginning wouldn't imply anything one way or the other about whether causality has a beginning. If abstract math doesn't convince you, just consider the possibility that what we think of as "the universe" is actually a simulation (which it might be for all we know). Just because the computer running the simulation doesn't start counting simulated time until it simulates a Big Bang doesn't mean it wasn't executing instructions in a cause-and-effect sequence while it was getting itself set up to simulate a Big Bang. So unless you can prove our universe isn't a simulation you have no grounds for jumping from a beginning of our universe's time to a first cause.
Or do you disagree about the standard model of physics breaking down and not telling us what was happening before the Planck Time? If so, tell me, as a matter of logic, how there could possibly be evidence for an actual singularity at Time Zero. Big Bang cosmology is based on starting with observation of current conditions and mathematically running the laws of physics backwards. We infer a hotter, denser past because the known laws predict that a hotter, denser world would change continuously into the sort of world we see now. That's how we deduce what the universe was like three minutes into the Big Bang, and three seconds in, and three nanoseconds in. But all of those laws say how a
finitely dense universe behaves. To extrapolate back to a singularity at the beginning of time is to say "It was infinitely dense, and then it changed to finite density." But we have no laws of physics to back us up on such an inference, no laws that say what happens when you start with an infinitely dense state. So there is no basis for predicting that a singularity would change into the sort of world we see now. So any extrapolation all the way to T=0 is illegitimate. Any physicist who does that is speculating, not reasoning. Why would you believe him, unless you think he's a demigod?
Without extrapolation to T=0, all we have is T=1, and before that T=0.1, and before that T=0.01, and so on, indefinitely. None of those times we can legitimately infer give a sign of being the Beginning of Time.
None of the foregoing depends on you believing in my expertise. Work the problem for yourself.