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Comment by redwards510 | Hacker News Reader

I don't believe in free will because of a simple thought experiment. Maybe someone with a background in ML can chime in.

Imagine we could perfectly map all your brain's neural connections at an instant in time to software. This is not out of the realm of possibility in the future, right? Now imagine we "asked" that model to make a decision. Any decision. Wouldn't that frozen-in-time model give the same answer every time?

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I use the same line of thought, but without any modeling. Suppose you could go back in time to a major decision in your life and make it over. But you arrive at that same point in time, with all of the same information you had, no new information about the future, with all of the same hormonal and biochemistry etc. Is there any way you could have chosen differently than what you did? I don't see how. Unless you want to introduce randomness, but that's also not choice.

This is not possible because of quantum mechanics. You cannot know the exact location and speed of particles in your brain and therefore cannot build a deterministic model to predict its behavior.

I think chaos theory suffices to establish your second sentence, without needing to bring in quantum mechanics.

https://en.wikipedia.org/wiki/Chaos_theory

Chaos theory is enough if you accept imperfect measurements, which would result in small changes in initial conditions. But you need quantum mechanics to prove that you cannot have perfect measurements of all the quantities involved in the evolution of a system.

It might give the same answer, but I'm not concluding much from the thought-experiment. The model takes as input its environment, which includes its past decisions. If you pose the same question to it twice, it might choose to do something different the second time just because it weighs "whimsy" as a positive. How random is its RNG? Can it tell? What would it do differently if it knew the answer to these questions?

And what if it did?

For me, the most important aspect of free will is to be able to predict the outcomes and consequences of my choices, use that as feedback to select which decision to make.

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