Readers who have stuck with me over the years will remember commenter 'Spur' whose comments were the best I received at the old Powerblogs site. Safely ensconced in an academic position, he now enters the blogosphere under his real name, Stephen Puryear. His weblog is entitled Second Thoughts.
No doubt you have heard of Hume's Fork. 'Fork,' presumably from the Latin furca, suggests a bifurcation, a division; in this case of meaningful statements into two mutually exclusive and jointly exhaustive classes, the one consisting of relations of ideas, the other of matters of fact. In the Enquiry, Hume writes:
Propositions of this kind [relations of ideas] can be discovered purely by thinking, with no need to attend to anything that actually exists anywhere in the universe. . . . Matters of fact . . . are not established in the same way; and we cannot have such strong grounds for thinking them true. The contrary of every matter of fact is still possible, because it doesn't imply a contradiction and is conceived by the mind as easily and clearly as if it conformed perfectly to reality. That the sun will not rise tomorrow is just as intelligible as - and no more contradictory than - the proposition that the sun will rise tomorrow.
One question that arises is whether Hume's Fork was anticipated by any earlier philosopher. Leibniz of course makes a distinction between truths of reason and truths of fact that is very similar to Hume's distinction between relations of ideas and matters of fact. See, for example, Monadology #33. In a very astute comment from the old blog, 'Spur' details the similarities and concludes:
Leibniz and Hume have the same basic distinction in mind, between those truths which are necessary and can be known a priori, and those which are contingent and can only be known a posteriori. The two philosophers use slightly different terminology, and Leibniz would balk at Hume's use of 'relations between ideas' in connection with truths of reason only, but the basic distinction seems to me to be the same.
I deny that the basic distinction is the same and I base my denial on a fact that Spur will admit, namely, that for Leibniz, every proposition is analytic in that every (true) proposition is such that the predicate is contained in the subject: Praedicatum inesse subjecto verae propositionis. I argue as follows. Since for Leibniz every truth is analytic, while for Hume some truths are analytic and some are not, the two distinctions cannot be the same. To this, the Spurian (I do not say Spurious) response is:
The [Leibnizian] distinction is between two kinds of analytic truths: those that can be finitely analyzed, and those that can't. This is an absolute distinction and there are no truths that belong to both classes. Even from God's point of view there is presumably an absolute distinction between necessary and contingent truths, though perhaps he wouldn't view this as a distinction between finitely and non-finitely analyzable truths, because his knowledge of truths is intuitive and never involves analysis.
I grant that the two kinds of Leibnizian analytic truths form mutually exclusive and jointly exhaustive classes. But I deny that this suffices to show that "the same basic distinction" is to be found in both Leibniz and Hume.
One consideration is that they do not form the same mutually exclusive and jointly exhaustive classes. Though every Humean relation of ideas is a Leibnizian truth of reason, the converse does not hold. I think Spur will agree to this. But if he does, then surely this shows that the two distinctions are not the same. I should think that extensional sameness is necessary, though not sufficient, for sameness.
But even if the two distinctions were extensionally the same, they are not 'intensionally' the same distinction.
Consider Judas is Judas and Judas betrays Christ. For both philosophers, the first proposition is necessary and the second is contingent. But Leibniz and Hume cannot mean the same by 'contingent.' If you negate the first, the result is a contradiction, and both philosophers would agree that it is, and that it doesn't matter whether the proposition is viewed from a divine or a human point of view. The negation of the second, however, is, from God's point of view a contradiction for Leibniz, but not for Hume. For Leibniz, the betrayal of Christ is included within the complete individual concept of Judas that God has before his mind. So if God entertains the proposition Judas does not betray Christ, he sees immediately that it is self-contradictory in the same way that I see immediately that The meanest man in Fargo, North Dakota is not mean is self-contradictory.
Of course, for Leibniz, it is contingent that Judas exists: there are possible worlds in which Judas does not exist. But given that Judas does exist, he has all his properties essentially. Thus Judas betrays Christ is contingent only in an epistemic sense: we finite intellects see no contradiction when we entertain the negation of the proposition in question. Given our finitude, our concepts of individuals cannot be complete: they cannot include every property, monadic and relational, of individuals. But if, per impossibile, we could ascend to the divine standpoint, and if every truth is analytic (as Leibniz in effect holds via his predicate-in-subject principle), then we would see that Judas betrays Christ is conditionally necessary: necessary given the existence of Judas.
'Contingent' therefore means different things for Leibniz and Hume. Contingency in Hume cuts deeper. Not only is the existence of Judas contingent, it is also contingent that he has the properties he has. This is a contingency rooted in reality and not merely in our ignorance.
Perhaps my point could be put as follows. The Leibnizian distinction is not absolute in the sense that, relative to the absolute point of view, God's point of view, the distinction collapses. For God, both of the Judas propositions cited above are analytic, both are necessarily true (given the existence of Judas), and both are knowable a priori. But for Hume, the distinction is absolute in that there is no point of view relative to which the distinction collapses.
I'm stretching now, but I think one could say that, even if Hume admitted God into his system, he would say that not even for God is a matter of fact knowable a priori. For the empiricist Hume the world is radically contingent in a way it could not be for Leibniz the rationalist.
One source of its appeal is that it reinstates much of what was ruled out as cognitively meaningless by logical positivism but without rehabilitating the commitments of old-time metaphysics. Permit me to explain. (My ruminations are in part inspired by Ernest Gellner, to give credit where credit is due.)
Crudely put, as befits a crude philosophy, logical positivism is just Hume warmed over. The LPs take his famous two-pronged fork and sharpen the tines. Hume spoke of relations of ideas and matters of fact, and consigned to the flames anything thing that was not one or the other. In the Treatise of Human Nature, he spoke of "school metaphysics and divinity" as deserving of such rude treatment. Since Hume's day, old-time metaphysics and theology have had a forking hard time of it.
The LPs spoke of two disjoint classes of statements and maintained that every cognitively meaningful statement must be a member of the one or the other. The one class contains the truths of logic and mathematics and such analytic statements as 'Every cygnet is a swan' all interpreted as true by convention. The other class consists of statements empirically verifiable in principle. Any statement not in one of these two disjoint classes is adjudged by the LPs to be cognitive meaningless. Thus the aesthetic statement, 'The adagio movement of Beethoven's Ninth exceeds in beauty anything Bruckner wrote' is by their lights not false, but cognitively meaningless, though they generously grant it some purely subjective emotive meaning. And the same goes for the characteristic statements one finds in theology, metaphysics, and ethics. Such statements are not false, but meaningless, i.e., neither true nor false.
Imagine a debate between a Muslim and a Christian. Muslim: "God is one! There is no god but God (Allah)!" Christian: "God is triune (three-in-one)." For an LP, the debate is meaningless since theological assertion and counter-assertion are meaningless. The assertions are neither analytic nor empirically verifiable. Or consider a debate between two Christians. They are both Trinitarians: there is one God in three divine Persons. But the man from Rome maintains that the Holy Ghost proceeds from the Father and the Son (filioque) while the man from Constantinople maintains that the Holy Ghost proceeds directly from the Father. For an LP, this debate about the procession of Persons is cognitively meaningless. I chose these examples to show how attractive LP is. For many of you will be inclined to think of these debates as in some sense meaningless. "How could one know one way or the other?" Many of you will be inclined to want to tie meaningfulness to empirical verifiability. Nevertheless, Logical Positivism is untenable. But that is not my present point.
My present point concerns the appeal of OLP. The OL boys weren't out to resurrect metaphysics. They took on board the anti-metaphysical animus of the LPs. But their approach allowed the salvaging of ways of talking that the LPs had no interest in preserving. Religious language is a key example. So what I am contending is that one source of the appeal of OL philosophy was that it allowed religious talk and thus religion itself to be saved from the forking accusation of meaninglessness. But it did this without crediting old-time metaphysics. You can see why that would appeal to a lot of people. To explain this properly would take a lot of scribbling.
But the central idea is that religion is a form of life and a language game, a self-contained language game that needs no justification ab extra. Hence it needs no justification from metaphysics or philosophy generally. It is in order as it is -- to use a characteristically Wittgensteinian turn of phrase. By the same token, religion cannot be attacked from the side of philosophy. It is an island of meaning unto itself, and is insofar forth insulated from criticism. (L. insula, ae = island.) Nor can it come into conflict with science or be debunked by science. Within the religious language game there are valid and invalid moves, things it is correct and incorrect to say; but the langauge game itself is neither correct nor incorrect. It just is. Religion is a groundless system of belief, a system of belief that neither needs nor is capable of justification. Since I reject both LP and OLP, I am not endorsing this view of religion. I am merely explaining one of the reasons why people are attracted to OLP: it allows them to practice a religion while ignoring both the threat from traditional philosophy (which demands the justification of key religious tenets) and the the threat of positivism which makes positive science the ultimate arbiter of reality.
Section VII of Book I of David Hume's A Treatise of Human Nature is relevant to recent investigations of ours into belief, existence, assertion, and the unity of the proposition. In this section of the Treatise, Hume anticipates Kant's thesis that 'exists' is not a real predicate, and Brentano's claim that the essence of judgment cannot consist in the combining of distinct concepts.