A Modern View of Determinism

A standard definition: Determinism is the philosophical idea that every event or state of affairs, including every human decision and action, is the inevitable and necessary consequence of antecedent states of affairs.

Interestingly, the implications of this seem to ‘feel’ quite a bit different whether one is backward or forward looking:

• Backward: Ah, this explains it!
• Forward: Something specific will happen; but what?

Prior to the discovery of quantum mechanics, determinism was generally assumed to operate along the lines of (simple!) billiard ball interactions.

Most physicists believe that quantum indeterminacy is ontological, not epistemological — an inherent feature of reality, not just a limit of knowledge. A small minority disagree.

Irrespective of this disagreement, what is now clear, is that it is physically impossible to measure those antecedent quantum states — destroying any hope of predicting outcome.

Another fairly recent development, chaos theory, is a second fundamental qualification of determinism: In certain dynamical systems (pretty much all of natural reality!) prediction will only be as good as the measurement accuracy of initial conditions. In other words, to totally accurately predict future states requires infinite precision — an impossibility. Additionally, in the real world, such chaotic behavior is also highly interactive, causing hyper-exponential uncertainty. Think about trying to predict the weather exactly one year from now at a very specific location: not possible, even in theory.

Startlingly, chaos theory has recently been shown to also apply to integer operations and even extremely simple logic rules! The only way to determine future states is to keep executing the rules — no shortcut is possible.

The clear implication of the these recent discoveries is that the only kind of determinism viable today is one that specifically excludes predictability — it is inherently impossible to predict the future of complex systems.

There are some exceptions, of course: for example systems specifically designed to limit uncertainty, or for outcome measured in aggregate.

Human activity in particular cannot be predicted — not even in theory.

Here I need to pause to refute the claim that ‘we could predict human behavior in theory’. No, not even in theory. One of Ayn Rand’s many brilliant insights was: If something is impossible in reality, then you cannot claim that it is possible in theory — a theory is invalid if it contradicts reality!

In conclusion, the inherent lack of predictability means that the only viable interpretation of determinism implies that the future is not determined in any meaningful way. It cannot in principle be determined. Ever.

Now I understand that it is hard to fully mentally and emotionally embrace this position as it is hard to comprehensively discard the idea that ‘we could maybe somehow find a way to measure the current state accurately enough…’

On the other hand, this new perspective opens up the possibility of humans having meaningful control over their destiny, and not just one based on the vagrancies of quantum dice. The only way we can know the future is by living it — while shaping it.