I think asking "what happened before the big bang?" is to an extent the same as "where do space, time and gravity come from?", but not in the sense that they're trying to obtain an external (to the universe) perspective.
The latter isn't trying to obtain an external perspective, but rather a more fundamental perspective, somewhat like how when you dig deep enough, the weak and electromagnetic force become unified, emerging from more fundamental properties. Similarly, with space-time and gravity being so heavily associated, there may be a more fundamental mechanism at work which is responsible for the properties of both.
The former is asking something potentially similar. In the early universe, there's a popular theory that the weak, strong and electromagnetic force were unified. Similarly, if the mechanisms for the properties of space, time and gravity can be unified, perhaps we may find that the big bang itself wasn't as much of a singularity as we think, instead being the result of some more fundamental properties of the universe being in a certain state. Thinking of it like the idea of a false vacuum decay, perhaps the fundamental properties of the universe were the same before the big bang, and the 'bang' was the vacuum dropping down to a more stable state, in which case "what happened before the big bang" makes some sense.
On the other hand, if the big bang was indeed the start of all physics including time, the big bang very well can have happened because this question would be asked.
As for our ability to perceive time shaping our way of thinking about it, from what I understand, we currently believe that physics holds under simultaneous charge, parity and time reversal. The various promising theories of quantum gravity have cases that might break this rule, which I think would effectively define a physical direction of time.
The latter isn't trying to obtain an external perspective, but rather a more fundamental perspective, somewhat like how when you dig deep enough, the weak and electromagnetic force become unified, emerging from more fundamental properties. Similarly, with space-time and gravity being so heavily associated, there may be a more fundamental mechanism at work which is responsible for the properties of both.
The former is asking something potentially similar. In the early universe, there's a popular theory that the weak, strong and electromagnetic force were unified. Similarly, if the mechanisms for the properties of space, time and gravity can be unified, perhaps we may find that the big bang itself wasn't as much of a singularity as we think, instead being the result of some more fundamental properties of the universe being in a certain state. Thinking of it like the idea of a false vacuum decay, perhaps the fundamental properties of the universe were the same before the big bang, and the 'bang' was the vacuum dropping down to a more stable state, in which case "what happened before the big bang" makes some sense.
On the other hand, if the big bang was indeed the start of all physics including time, the big bang very well can have happened because this question would be asked.
As for our ability to perceive time shaping our way of thinking about it, from what I understand, we currently believe that physics holds under simultaneous charge, parity and time reversal. The various promising theories of quantum gravity have cases that might break this rule, which I think would effectively define a physical direction of time.