Nor is it that truly a belief at all which has not some influence upon the actions of him who holds it. He who truly believes that which prompts him to an action has looked upon the action to lust after it, he has committed it already in his heart. If a belief is not realized immediately in open deeds, it is stored up for the guidance of the future. It goes to make a part of that aggregate of beliefs which is the link between sensation and action at every moment of all our lives, and which is so organized and compacted together that no part of it can be isolated from the rest, but every new addition modifies the structure of the whole. No real belief, however trifling and fragmentary it may seem, is ever truly insignificant; it prepares us to receive more of its like, confirms those which resembled it before, and weakens others; and so gradually it lays a stealthy train in our inmost thoughts, which may someday explode into overt action, and leave its stamp upon our character for ever.
This means that he is actually considering 'belief' in a fairly technical sense, because our ordinary use of the term is not this constrained. Fair enough. But he develops his account of belief in this sense in a completely lopsided way: the only case considered is the case in which the actions to which belief disposes us are bad. In "The Will to Believe" James shows that you can take exactly the same pragmatist analysis of belief, look at all the good actions, and draw the opposite conclusion, that it's often a good thing to risk believing beyond the evidence. And, of course, James is quite explicit about it, since this is his point about the fact that "Believe truth" and "Shun error", while complementary, are not the same command, and that Clifford's uncritical assumption that the latter takes precedence in every case can be questioned.
Much of the oddness of Clifford's argument derives from two sources: (1) The overblown rhetoric that arises from simply taking religiously-tinged moral rhetoric and inserting 'belief' wherever it talks about actions; and (2) the fact that the argument is clearly rigged to get certain conclusions, which in turn leads to rather implausible and poorly defended strictures. The two go together, to some extent: Clifford himself recognizes the implausibility of some of his claims, and tries to stifle the doubts by adapting moral rhetoric. He never really takes the trouble to show that his account of the ethics of belief complies with its own requirements, though; and this, of course, is another flaw James uses to his advantage, because much of Clifford's argument does not, in fact, comply with the requirements of the 'ethics of belief' it is defending. As James puts it, speaking of people like Clifford:
We slouchy modern thinkers dislike to talk in Latin,--indeed, we dislike to talk in set terms at all; but at bottom our own state of mind is very much like this whenever we uncritically abandon ourselves: You believe in objective evidence, and I do. Of some things we feel that we are certain: we know, and we know that we do know. There is something that gives a click inside of us, a bell that strikes twelve, when the hands of our mental clock have swept the dial and meet over the meridian hour. The greatest empiricists among us are only empiricists on reflection: when left to their instincts, they dogmatize like infallible popes.
And thus we have the irony, very deliberate on James's part, that while James's conclusions are inconsistent with Clifford's conclusions, James's argument is in greater compliance with Clifford's conclusions than Clifford's argument is.
