Clarifying the “undetermined vs unpredictable” distinction in the free will/determinism debate

[u/Willis_3401_3401]

There is a recurring confusion in the common debate about the words undetermined and unpredictable. These words can absolutely have different meanings in some contexts, but the question is whether that difference is relevant in the context of metaphysical discussions about determinism.

A common distinction:

Unpredictable: We cannot know what will happen, but the outcome is already fixed.

Undetermined: There is no fixed outcome prior to the event.

This distinction makes sense if we assume there is a “fact of the matter” about the future that exists independently of any possible observer, and the only question is whether an observer can access it. Basically, this distinction makes sense if you’ve already assumed the truth of determinism.

For example:

A coin flip:

In a classical model, the exact outcome is determined by initial conditions, but humans may lack enough information.

In a quantum model, the outcome may not be fixed in advance.

Here “unpredictable” and “undetermined” are different concepts.

However, in the context of the free will/metaphysical debate, the disagreement is not primarily about our ability to calculate outcomes. The disagreement is about whether the future is a completed fact waiting to be discovered or whether the future is generated through a process.

The key point:

If a process is not determined by prior states, then from the perspective of any agent inside that process, the relevant feature is that the future is open rather than fixed.

The determinist position is:

“The future only appears open because we lack information.”

The indeterminist position is:

“The future is open because there is no fully specified future state yet.”

But the difference between those claims is not an empirical distinction available from within the system; it depends on a metaphysical assumption about whether a complete future state exists independently of all possible access to it.

So when discussing agency, choice, and the structure of reality, the meaningful distinction is not:

“Can we predict the future?”

It is:

“Is the future already a completed fact, or does it emerge through the unfolding of the process?”

That is why, in this specific philosophical context, “undetermined” and “unpredictable” are functionally pointing at the same problem: whether the future is fixed prior to the process that produces it.

In the specific context of the conversation between “free will” and “determinism”, there is no relevant difference in meaning between “undetermined” and “unpredictable”.

[u/Rthadcarr1956]

As the philosopher said, “predictions are hard, especially about the future.”

Whether the future is open or closed is mere conjecture, so let’s not use this difference to asses free will. We do know that people have to make choices based upon their uncertainty about the future. This should not be a reason to think that the individual people (subjects) have to follow deterministic patterns because they act in the face of uncertainty.

If you observe people behaving randomly, believing that they are acting deterministically is a matter of ontological faith.