Labels exist, and in philosophy there is way too much jargon. That being said, many people know some terms that they might label a person and are unfamiliar with others that they never will. It seems the word “determinism” is common enough for many people who have an interest in the topic of free will and some even know what “hard determinism” is. On the other hand the term “Hard Incompatibilism” isn’t as spread around as these other words. And though it has differing usages, it’s been adopted by Derk Pereboom (Living Without Free Will) and others to address indeterminism as well.
When someone learns you don’t believe in free will, one of two things seem to spring to mind. Either they think your position is a religious one, meaning that since God knows everything you can’t have free will. In other words you believe in predestination “fated” by a deity (which would be true if such an all knowing deity existed). Or they think you are a hard determinist: that you believe every event has a cause and that due to this our decisions stem back in time to causes that precede back to the start of time.
The latter is much closer to my position on the matter, but it’s not exactly accurate. Though I think it’s highly likely that all events have a cause, at least in our known universe after the Big Bang, I’m agnostic on the possibility of some events being without any cause at all (as crazy as not having a cause may sound). At the quantum scale (basically as small as we can go), some quantum interpretations postulate truly non-causal events (what I call acausal events in my book), and others are entirely causal (though nonlocal – a term I won’t address here). Other interpretations are agnostic to both. In physics, there seems to be a mixed bag of different interpretations surrounding the mathematics and experiments that show some very interesting and wacky things. On that scale there are various unintuitive problems with both causality and non-causal events.
Needless to say there is a possibility that the universe is “indeterministic” meaning a mix of causal and uncaused events. The problem, however, is that both a deterministic universe and an indeterministic universe are incompatible with free will. So if the universe is deterministic, I truly do fall under “hard determinism”. The problem with that is it excludes an indeterministic universe, which I see as, at the very least, an unintuitive possibility.
The term hard incompatibilism, however, is all inclusive. It means that both possibilities, determinism and indeterminism, are equally “incompatible” with free will. Due to this it’s a stronger position on the lack of free will than hard determinism.
The reasons why both possibilities are incompatible with free will is much, much more complex, and detailed out in great lengths in my book Breaking the Free Will Illusion for the Betterment of Humankind. This post isn’t about making the case against free will, but rather explaining what Hard Incompatibilism is, how it differs from Hard Determinism, and how it covers more.
The fact that people contrive free will based solely on the possibility of indeterminism in the universe makes it of utmost importance that we cover that base as well. And it turns out that not only is an indeterministic universe as incompatible with free will than a deterministic one, but it’s also much more of a detriment if any single non-caused event has a direct say in what we think or act.