Determinism

[Dr.Love]

@Half_Man_Half_Wit

Not sure I get this – the list was created in a deterministic way, and my reading it is completely deterministic, too. You seem to presume that ‘reading the list’ is independent of its history, but as I said, one has to take into account the whole system in order to decide whether or not it is deterministic.

That which didn’t make it to the final cut, or which was never filmed in the first place. A film is one particular part of the (deterministic) events surrounding the making of the film – the actor’s actual actions for instance, including moving from set to set, changing costumes, etc., which in total all occurs such that every action follows from the previous one. The film is merely an incomplete sampling of this, just as the sequence 1211631 is a sampling of the deterministic production of all possible dice throws; its apparent randomness is a result of its incomplete context.

In order to talk about whether a system is deterministic, we need a state space, and a evolution parameter. In a Newtonian universe, the state space would describe the positions and velocities of all the particles in the universe. In modern physics, the state space is more complex, involving wave functions and other such things. In a movie, the state space describes the colors in a two-dimensional array of pixels. In our universe, the evolution parameter is time. In a film, the evolution parameter is the frame number. Determinism is the property of a system that, given complete knowledge of all* “past” states, you can determine the next (“future”) state.

Under this definition, a film is clearly indeterministic. It’s not indeterminate on account of being open. Once a film is produced, it doesn’t interact with the world around it. Nor does the “history**” of making the film matter, since the process of making it cannot be represented in the state space. So, do you disagree with my definition of “determinism”?

If you want to change the definition of determinism to include requirements on how the system was created, you’re going to run into problems. Under my definition, Conway’s Game of Life is a deterministic system. If, however, we need to know how the game was created, then we can’t say whether it’s deterministic without also knowing whether Conway was deterministic. Consequently, we can’t know whether any system is deterministic until we know whether the entire universe is deterministic. Or worse, physicists may find several models of physics consistent with reality, some of which are deterministic and others that aren’t. If that turns out to be true, the question of whether any closed system is deterministic would be unanswerable.

If you still want to include requirements about how a system came to be, realize that these requirements will break the chain of causation, destroying the argument that free will is incompatible with determinism.

@Half_Man_Half_Wit

I’m pretty much out of the discussion at this point, but there’s one question I never seem to be able to find a good answer to: if for some event there does not exist sufficient reason (i.e. if it’s not determined), then how does it happen? How can something be truly random? If two possibilities, A and B, are equally likely to occur, what happens in order to choose, say, B over A? I’m not asking why B happens, but merely how – what is the process through which something happens if it is not determined to happen? I know, the answer typically is ‘there is no process’, or ‘it just happens that way’, or anything along those lines. Both A and B could happen, and B happens, that’s all. Most people seem content with this, but to me, this seems to be a deeply unsatisfactory answer. In order to choose B over A, surely somehow, somewhere, a choice must be made. But how can that choice be made if there is no sufficient reason for it? It’s a well-posed question, but it doesn’t seem, in principle, answerable – since any answer would provide a determining mechanism, and remove the stipulated randomness. If I were to accept this, I should just as well accept ‘God did it’ as ultima ratio.

I don’t know what the mechanism is. If you figure it out there’s a Nobel, or maybe a Field’s Medal in it for you.

*A slightly weaker version of determinism would only require knowledge of a single previous state.

**In quotes because “history” refers to time, and not to frame count. Time is not the appropriate evolution parameter for a film. The question of whether a film was deterministic still makes sense if you lay the frames out side-by-side, rather than flash them on a screen one at a time.