If consciousness causes collapse, then wouldn't physics shortly after the big bang be different?
Consciousness deos not collapse the wave function. Measurement does, and it does because of the energy required to measure the particle's position.
I am admittedly not a studied physicist. (So the following is my understanding, and someone should correct me wherever I am wrong.)
Consciousness does not cause the collapse, in the sense of the famous thought experiment posited by Schrödinger. It instead is the process of measurement, and conscious awareness requires measurement, (whether that is by instrumentation or natural sensory input).
This is because any process which measures the state at a given moment of any quantum state introduces new energy to a particular thing being measured, and thus alters its state, "collapsing" it.
I am sure someone else can give you a more linguistically correct explanation, but this is the understanding I have in relatively casual terms, (as your question appeared to be a more casual one).
Oh no no, I don't believe consciousness causes collapse. I'm just wondering whether the fact that wavefunctions appear to collapse shortly after the big bang could be used as an objective refutation of the CCC position.
You don't need consciousness for collapse. You need an observer. A planetoid recording asteroid impacts with its surface craters makes a sufficiently good observer. Though, considering world from perspective of a planetoid is a bit boring.
The question is actually quite a bit difficult, and no clear answer is understood, because it really depends on the depth intended in the question itself. Many here will be quick to tell you that "collapse" is a decoherence phenomenon-- a quantum state can involve many possible measurable outcomes at once because of the "purity" of the state, which encodes "coherences" between these various outcomes in such a fundamental way that you have to conclude they are all sort of "rolled up" into the current state of the system. Those coherences allow the state to in a sense "contain all the outcomes at once". But coupling that state to a much more complicated system, like a macroscopic measuring device or the brain that interprets the outcome, wrecks those delicate coherences and puts the quantum state into a more mundane type of combination of the outcomes-- the combination that says "the measurable has taken on one of the definite values, we just don't know which until we look." None of that requires consciousness, or even an observer, at that superficial level of description.
The problem is, that superficial level quickly breaks down when you dig deeper into it, and that's how you end up with "interpretations" of quantum mechanics, like Copenhagen, Many-Worlds, or deBroglie-Bohm. It also requires digging into what is it that you mean, in your question, when you use the word "causes." At a superficial level of the everyday doing of physics, a "cause" is a pretty clear and powerful idea. But when you dig into it, at the level of "what is really going on" in wavefunction "collapse", you quickly find that the everyday notion of a "cause" is unsuitable, and indeed it's not clear that there is any such thing as a true "cause" in physics at all.
If you want to try and say further what you mean by "causes" wavefunction collapse, that could be an inroad to digging more deeply into the question. Suffice it to say that the answer to your question, I would say, depends critically on what we think physics is in the first place-- for example, we must ask if physics is supposed to be a description of what is really happening in the world, or if it is simply supposed to be how we as human beings interact with and make sense of our world, in ways that are not at all independent of our own unique goals and limitations. It is that latter place where the real question of "what consciousness is responsible for" in physics becomes inescapable, and is also an interesting point of entry into the key differences between the above interpretations.
Ken: Isn't what you're describing more Ontology than Physics?
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