Warning! This is a very dogmatic post. Not, of course, that my other posts are never dogmatic....
There is an interesting post by Neal Tognazzini at the philosophy weblog, "The Garden of Forking Paths," on the question of what is really meant by 'determinism'.
I think it's about time people started asking this question, because, quite frankly, the only reason 'determinism' hasn't been completely demolished and banished from the intellectual scene is that 'determinists' significantly change their position every ten years or so. (Yes, this is my very non-determinist libertarian view; God only knows how determinists themselves would explain it. Hence the need for people to start asking the question.)
This shiftiness irritates me, in case you haven't figured it out from my tone.
For instance, there is the view noted by the author of the post, namely, that determinism is the position that {past + laws of nature} entails one single future. (It always seems to me that exactly how they entail it is always nudged under the rug a bit, but that's a side issue.) But this is a fairly recent view; the farther back in time you go from the present day, the harder it is to find it. The farther back you go, the more it is entirely about causes. (How the causes entailed a unique future was always nudged under the rug a bit, too, but that's also a side issue.) The exact variation varies considerably from decade to decade, depending on what's fashionable. To make matters worse, scientists at some point began using the term differently than philosophers, and now there's a weird feedback loop going on. It's all a mess.
This occasionally happens in philosophy, i.e., a label, for purely historical reasons, is retained through radical transformations that make it an endless invitation to equivocation. 'Determinism' isn't actually the worst example; the worst example is 'materialism', which has been used for so many mutually exclusive positions, and has been adapted to so many facts that would previously have been considered not materialistic at all, that it is only just this side of useless. 'Determinism' is in a fair way to that.
This wouldn't be a problem - just an issue about labels - if it weren't for the effects it has on the discussion. (1) We libertarians can never assume anything about 'determinism', because it's something different half the time it comes up. The pro-free-choice position has varied through time, as all philosophical positions have, but there have been several stable themes that unite the whole: the phenomenology of choice, self-mastery, moral responsibility, etc. Not everyone takes precisely the same view or has precisely the same theory of these, but libertarians have been fairly constant and dependable in appealing to the same facts as the foundation of the position. Not so with 'determinists', since that label indicates theories built on some rather different foundations through time. (2) Contrary to first impressions, there hasn't been a continuous free-will vs. determinism debate in philosophy. Rather, there have been a whole bunch of smaller debates in which the basic core of the free-will position has outlasted every one of the fashionable contenders brought against it as its new certain nemesis. This important truth has been obscured both by the shiftiness of the 'determinism' label and by the odd fact that every 'determinism' is always put forward with triumph as a relatively problem-free position that is far superior to the free-will position - and it is never more triumphalistic than when it is just about to morph into something completely different. So advocates of the free-will position should take heart; it's a long hard fight agains the forces of unreason, but we've always been here before and survived....
Now, calmness is returning.
Note added later: I should say, now that my rant is done, that it is entirely possible to defend a particular version of determinism without any intentional shiftiness. But in general philosophers who call themselves determinists help themselves to a level of credibility and assume for themselves a level of stability their actual position has not earned, precisely because they do not take sufficient care to avoid this sort of shiftiness. This is most obvious in the so-called Problem of the Intelligibility of Free-Will. The assumption is generally that 'determinism' is the more intelligible option, and that the libertarian position has to go to greater lengths to show that their position is intelligible. There is no such problem. The free-will position is less obscure, first, since its primary appeal is directly to experience, and second, because no particular determinist position has actually shown itself to be both intelligible and capable of recognizing all the facts of human choice; thus the real discussion should always be about the Problem of the Intelligibility of (this particular variant of) Determinism.
