In one sense, chance is opposed to necessity and in another sense it is opposed to intention. The first sense has two main senses: on the one hand there is chance as opposed to probability (where chance favors no outcome) and in another (broader) sense there is chance as compatible with probability (like “games of chance”).
The way in which chance is opposed to intention is not immediately given. For example, it is not clear that because we can take “chance” and separate it fro intention that chance can be separate in reality. “Pure chance” might well involve a contradiction.
Just Thomism 
Edward the Lesser said,
December 9, 2009 at 8:22 am
At the heart of this seems to lie the point you have persistently been making on this blog: imagination is not a source of real possibility. It seems like this idea had its origin in Descartes and was then carried to an extreme by the empiricists. However it got here, it is held onto dearly by most modern philosophers. I have merely suggested that this idea might be incorrect in several of my classes and my teachers have no idea how one could possibly object to this idea (they cannot imagine how, apparently).
James Chastek said,
December 9, 2009 at 10:08 am
Right. Possibility by fiat has a similar effect to fiat currency: inflation. Possibility becomes cheaper and cheaper as it is assumed that anything is possible, and that we can mint a new possibility simply because there is some sense in which we can imagine it. Utterly absurd theories- which are in fact have nothign but a logical unity- are seen as being real possibilities that must be taken in earnest.
Martin T. said,
December 9, 2009 at 12:44 pm
As a non-philosopher i’ve seen eg: athiests argue that a FSM could have created the universe and died and, because it is possible, it must be conidered equal to a creator God. if this is the sort of arguement you mean how do you refute the possible means equal hypothesis?
James Chastek said,
December 9, 2009 at 6:26 pm
In general, we need to ask more frequently “why is that possible?” or “what reason do we have to think the being you are speaking of is even possible?” Possibility is either a kind of existence, or it is not. If not, then claims about possibility aren’t that interesting; if so, then possibility needs to be proven, demonstrated, or simply be obvious. But we have to stop thinking that just because we can think of something that we must treat it as a real possibility.
Joseph A. said,
December 9, 2009 at 2:18 pm
James,
Isn’t chance, as far as proper science and normal inquiry goes, always either a statement of ignorance or, at best, a statement about a part of a model?
By that I mean, it’s not like we ever can look at something and go, “Aha! I see chance!” It’s rather like saying, “Aha! I saw something come from nothing!”
Mike said,
December 9, 2009 at 2:45 pm
It is possible to draw a card from a deck and it is an ace. It is also possible that it be a spade. But aces and spades are not equally possible.
I once had a fruitless discussion with a fellow who insisted that since a drawn card was either an ace or it was not, the two possible outcomes must be equally likely. He was invincible in his ignorance, even when invited to perform the experiment.
James Chastek said,
December 9, 2009 at 3:27 pm
Joseph A,
There is a very long history of denying the reality of chance, and there is some force to it- the sciences not infrequently find causes for things thought to be by chance, like the generation of gnats, or hand washing and patient health.
Here is the important distinction between luck and chance. It wasn’t important here, but it is important in itself. Luck (good and bad) results from some ignorance or deficiency in the power of the agent, chance in nature proceeds from some deficiency in interior causes, primarily from matter.
Aristotle called chance a real cause, but cause per accidens. It is not a proper cause, but it is that which is responsible for something, and so satisfies some notion of cause. This is a tricky question, one that De Koninck dedicated much of his career to.
James Chastek said,
December 9, 2009 at 3:29 pm
Mike,
That’s a wonderful example of so many things.
Joseph A. said,
December 9, 2009 at 9:39 pm
James,
Well, I’m not really going so far as denying the reality of chance. I’m just asking a question (well, at this point defending a view) which, I think, illustrates the difficulty of talking of chance.
And yes, I think Mike gave a great example. But it’s also an example showing how ‘chance’ (which many times gets mixed up with ‘unguided’ or ‘purposeless’) is abused again and again. I think the problem is actually as big as the when talking about “blind” forces, which you now and then tackle.
Mike said,
December 10, 2009 at 8:39 am
“Chance” v. “purposeless” is indeed a mixup. One usually has a reason for cutting cards.
Ben Espen said,
December 10, 2009 at 11:16 am
So material things are not perfect enough to truly be be deterministic?
James Chastek said,
December 10, 2009 at 2:15 pm
yes. That was exactly De Koninck’s point too- a “nature” that was perfectly determined could not be nature. Matter is always a source of unintelligibility to some extent ot another.
Robert said,
December 12, 2009 at 1:27 am
This is a fascinating idea:
a “nature” that was perfectly determined could not be nature.
I don’t exactly understand what you mean by it, though. I think I don’t understand what you mean by the word nature. Why is a determined nature contradictory?
James Chastek said,
December 12, 2009 at 6:48 am
When I said that an utterly deterministic nature was a contradiction, I was thinking most of all about the reality of matter, which is essentially indetermination. But there are less theoretical ways of looking at it too. Consider the view of the world on pure determinism. The claim is that “reality” is a process that unfolds with all the perfectly intelligible rigor of a syllogism, and with all the exact precision of a basic arithmetic problem. Is that how nature looks? Isn’t nature more like art so far as it seems to tolerate some amount of imprecision on the margins, and to work within margins of error?
The determinist might respond to this that the error was itself the result of some determined process, and any error in that process was due to another error ad infinitum. But after this infinite stream opens up, it starts to become clear that all we are saying is “the effect must happen because it must happen”
Or is there more than this? Isn’t the determinist idea based on the idea that there will always be a perfectly intelligible set of causes to anything that happens in nature? Moreover, don’t we have to assume that these causes are perfectly intelligible to us? Perhaps this would be the case if the only cause working in nature was a mathematical form- and physics after Galileo, of course, believed exactly this, and the view never disappeared. This is why the claim that science studies “only material and efficient causes” is too quick- mathematical physics more seeks to reduce everything to a formal cause, that is, to an abstracted mathematical form. In fact, material and efficient causes make it impossible that nature be perfectly intelligible to us, and make determinism impossible! On the one hand the line of causality in nature ends in prime matter; on the other hand the line of efficient causality ends in the first unmoved mover. Both are known to us only by analogy or comparison to sensible things and neither is known in itself by a direct vision, at least not as we exist now. The ultimate justification of determinism- that all things have a cause intelligible to us- is a deeply mistaken view of nature, one which silently assumes that our intellect could be the sort of thing that could give rise to nature.
Niggardly Phil said,
December 10, 2009 at 1:54 pm
Maybe Joseph A you could say something about this “ignorance” in your first post – I take from what you said it is something that could or should not be (if we knew more, we could account for everything per se), but from James that it is something that cannot be dispelled. One cannot reduce chance to something else, it seems to me.
Niggardly Phil said,
December 10, 2009 at 2:01 pm
Chance is not in our knowing and accounting, but in reality.
Joseph A. said,
December 10, 2009 at 3:17 pm
Niggardly Phil,
As I said with James, I’m not trying to argue here that there’s no such thing as chance. Just that there’s a difficulty with it (James himself gave examples of things once ascribed to chance which turned out not to be the case, and at least implied some of the problems with “pure chance”), and that even the idea of chance is often abused (one way, as Mike pointed out, being that it gets mixed up with ‘purposeless’).
To observe something and to not immediately have an explanation for it, or awareness of an intention behind it occurring, is not to ‘see chance’. Or at least, that what was observed is owed to chance is something that’s going to take a lot more to argue for, and I think is going to kick someone right outside the limits of what’s commonly regarded as science.
I’m not speaking here against Aristotle or Aquinas (indeed, I’m inclined to think they make sense of ‘chance’ more than most).