The meaning of determinism

NOTE HXA7241 2021-03-28T08:16Z

What does determined/deterministic mean? It cannot merely be a kind of abstract, implicit quality ‒ it must be about knowing outcomes.

It cannot mean just that you followed certain steps, or that certain ingredients were involved. You could do that and leave gaps unspecified, so the process would still not be deterministic.

But it is also not enough to say that all steps were followed and there are no other influences. That is the mathematical process case: there are certain generating rules, and nothing else contributes, therefore it is deterministic. But this also falls short.

This is the idea that what you build from deterministic parts is itself (thereby) deterministic ‒ there is no gap for indeterminism to creep in, right? No, that must be wrong. The determinism of the whole is defined separately from the parts, just as the meaning, the behaviour, is defined separately from the parts. You cannot completely describe the whole only from the parts, so you cannot describe whether it is deterministic only from the parts. You are talking about a different model. Different models leave different stuff out.

The substance, the value, in the idea of ‘determined’ is that you know what you will get. If someone sells you a process, telling you not to worry, it is 100% deterministic, and then you read the fine print saying that they only half know what the results will be, you will want your money back. So when people say something is ‘deterministic but not predictable’, it seems that there is something amiss.

For something to be determined, you have to know all the influences, and furthermore, you have to know what it will do. Think: how do you know something is even an influence on a process? You have to know that it affects it. And that means you have to know what it will do (or not do, which is the same thing). So this whole matter is about knowing what things do – you cannot escape that.