However, it's predetermined by B knowing what will happen. Although B will not influence A, it's still a predetermined decision.
One caveat. Whether
A drops the toast in a Universe without time travel will always remain unknown.
In our original universe, we have this equation:
a + b (past selves of
A and
B) ->
A + B (future selves, post toast incident)
Now if
b were to go into the future and view the result of the toast incident, then travel back into the past, you would have:
a + b(X) (representing difference in
b due to foreknowledge) ->
A + B(X) + b
In other words, the future
A + B no longer exists.
b's actions have created a new future. And in that future, whatever
b did or did not do,
a still dropped the toast. But
b does not have the power to change the situation. Thus he cannot influence
a's actions
once he knows the future. Causality is preserved.
Alternatively, if
B travels to the past:
a + b ->
A + B
turns into:
a + b(x) + B ->
A + B(X)
turns into:
a + b(x) + B(X) ->
A + B(X) + B(XX)
With
B now caught in an unending closed time-like loop.
-----
Quantum interactions are
only random if nobody observes them. And they're not so much random as undefined. Observation of quantum effects collapses the wave function and defines them. Note: Schrodinger's cat... whether it is dead or not is only random until you open the box.
It is likely the future is like this, too. It's in this way that
b collapses the wave function and make that one future a certainty.
There's already precedent for this in quantum mechanics. Observing the spin or orientation of one of an entangled pair of particles means that you now have knowledge of the spin or orientation of the other particle. And if that particle is one light year away, it would be impossible to know said spin or orientation via other channels (say, a radio burst from the research station where the other particle is being observed) for at least a year. Congratulations. You've just looked into the future!
But there is so far no way for us to use this quantum effect to transmit messages back into the past... because we can only observe these phenomena, not alter them or make them exactly what we want.
-
There is no actual physical law that prevents time travel. It's just that all the known mechanisms that permit it are unavailable to us at the moment.
So if time travel ever becomes possible, where are all the futurelings?
Posted in the other thread... they're spitting out of time in interstellar space, light years from the Earth... which will only reach the point where they come out of the future at the exact moment they travel back into the past.
So... when the first time machine back into the past launches, expect the launch to be preceded by a meteor strike. Or a shower, depending on how large the time machine is. If it's made by NASA, it'll probably be the size of a building.
And if they want to make it capable of moving in space to reach where the Earth is in the past... maybe the size of a city (plus reaction mass). Then something goes wrong with the engines and the thing crashlands on Earth, 65 million years in the past, killing off the dinosaurs and blanketing the globe with a fine dusting of iridium ash.
But without God that does not automatically make free will true. As Descartes describes, we could be under the influence of an unknown force or demon. This is best interpreted as "The Matrix" scenario.
The issue I see with looking at free will in this manner is: if it feels like ice cream, if it looks like ice cream and if it tastes like ice cream... why not call it ice cream?
Whatever process or mixture of processes creates consciousness, it feels real to us, and that's the only thing that matters. Whether we're programs running on a quantum computer, biological mechanisms with an intricately complex biofeedback system that simulates consciousness or otherworldly spirits inhabiting corporeal bodies, we can still feel emotions, we can think, we can rationalize, we can do purposeful action and we can create new things and appreciate things thus created.
Those of us without brain damage, that is...
Given that we think we have consciousness and exhibit all the signs of having it... who's to say it's not there? We pass the Turing test, don't we? (at least I do.)