I was reading this answer regarding materialism and free will. It says that, under the assumption that there isn't a random process underlying decision making, there is no free will.

And isn't that a very big assumption, not knowing how the brain works? I mean, if the brain has such immense machinery, is it difficult to add a stochastic component? A circuit spitting out random numbers?

What if there is a totally unprimed clear brain that has to decide to take one of the roads at a fork. Although this is unlikely since the brain usually encounters enormous information even before it is capable of or old enough to take such a decision, consider it as a thought experiment.

Couldn't the brain choose a left or a right based on this circuit yielding random numbers? Even if it did, would it be called free will?

  • +1 The concepts "random" or "determined" already assume there is no free will agent causing the event that is observed. But it is not necessary to make that assumption. One can assume some agent was responsible for what happened. Then the agent determines or causes what happened and it is no longer random. Feb 24, 2018 at 19:59
  • If the brain has a random component, what would be the physical basis of such a mechanism? Do you have proof or evidence that there's randomness in the world? Even quantum "randomness" may be due to our own lack of knowledge, not any inherent property of the world. Nobody knows.
    – user4894
    Feb 24, 2018 at 20:15
  • Well there are algorithms to generate pseudo random numbers atleast @user4894
    – Polisetty
    Feb 24, 2018 at 20:24
  • @Polisetty I hardly see the relevance of pseudorandomness if one is trying to make a philosophical point. A psuedorandom sequence is perfectly deterministic. A better (but still wrong) example would be the flip of a coin, or the low-order bit of the femtosecond timestamp of the arrival of an alpha particle at a detector. In the case of a coin, the randomness is due to our lack of knowledge of the exact air pressure, force and angle of the flip mechanism, etc. In the case of radioactive decay, it might be exactly the same: that if we had sufficient knowledge, it would not be random.
    – user4894
    Feb 24, 2018 at 22:52
  • @user4894 "In the case of radioactive decay, it might be exactly the same" ...not according to Bell's Theorem.
    – H Walters
    Feb 25, 2018 at 0:06

1 Answer 1


I think it's a big assumption, but not without some merit.

Firstly, we don't know if there are truly random events at all. To say that an event is random means that we don't have sufficient information (and method of calculation) to determine the exact outcome. But we cannot be absolutely certain that such information doesn't exist (e.g. some yet-to-be-discovered hidden variables) or may not eventually become available to us.

So, one can at least reasonably entertain the possibility that there are no truly random events at all -- and in this case, there wouldn't be any random processes in the brain (and decision-making, etc), either.

Secondly, to quote George Musser (in reference to Butterfield, Dennett and List), "human cognition involves different structures than atomic physics and is governed by different laws, so determinism at micro level need not imply determinism at the agential level." As an analogy, if you consider a process like gas expansion, the behavior of individual particles may be random, but certain "important" aspects of the "overall" behavior of the system are quite deterministic.

So, in this case as well, it may be possible to view the brain as a deterministic mechanism (perhaps to some extremely high degree of accuracy) on the level of decision-making, even if you allow random events on a small scale.

Now, as to your last question, if we were to grant that the decision-making mechanism is "truly" random, then it's very difficult to reconcile it with (at-least) a common-sense meaning of free-will. In this (common) sense, free-will implies "control" over the choice being made. However, if the decision-making mechanism is random, then to talk of "control" is (nearly) as meaningless as in the case when your decisions are determined by material/physical factors. So, at the very least you'd have to redefine the meaning/scope of "free will". Of course, people are certainly trying -- and it's worth reading about (here's one overview: https://www.scientificamerican.com/article/quantum-physics-free-will/).

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