Proving Determinism: A Thought Experiment

Leveraging computer science for answers to a classic philosophical question

Evan Kozliner
21 min readJan 11, 2020


Authorship is just one of the many challenges facing a deterministic worldview. Why give anyone credit for something they never chose to do? Source

“God grant me the serenity to accept things I cannot change,

Courage to change things I can,

And wisdom to know the difference.”

— Reinhold Niebuhr

Everyone at least acts as though they have the power to make their own decisions. Yet, when we reflect upon what we know about the natural world, it seems like this shouldn’t be possible. Instead, the thoughts you have should be cold, neurochemical reactions you have no control over. Similarly, chance must also be an illusion. If you win the lottery, the luck you perceive wasn’t really luck at all: turning the clock back would yield the same result over and over again.

Serious belief in the idea that “all things happen for a reason” is referred to in philosophical circles as Determinism. Determinism appears to be a natural consequence of the laws of nature and what we’re taught in physics. In this post, I’ll argue that from within a deterministic world — even one with trivial laws governing it — there’s no way to know if the world is truly deterministic. Along the way, I’ll also do a brief dive into why I don’t find the state of physics sufficient for figuring out if the world is deterministic, set criterion for what a good answer looks like, and teach you a fair amount about Conways Game of Life, a famous computer program.

“The world is governed by (or is under the sway of) determinism if and only if, given a specified way things are at a time t, the way things go thereafter is fixed as a matter of natural law.” — Stanford Encyclopedia of Philosophy

Where Physics Falls Short

Many people are allergic to philosophical speculation based on physics. Here, I explain why. You can skip this section if you really want, but you shouldn’t. The arguments in this area are fascinating, even if they’re incomplete.

This section isn’t necessary to understand the argument. Instead, it is the motivation for…



Evan Kozliner

I write about technology, philosophy, and their intersections