This is an essay I wrote for my Philosophy 501--Philosophy of Religion final. It's an interesting one to post on line, because it was open-ended: basically give your thoughts on everything we had studied that semester, which had revolved around three philosophers. I think it says a lot about my basic philosophical perspective.
Hume: Hume's philosophy of religion needs to be understood in the context of his philosophy as a whole, which contained two main points:
*Empiricism: Hume divided all knowledge into "relations of ideas" (such as mathematics) and "matters of fact" (empirical knowledge). Only relations of ideas can be known a priori, and how ideas apply to the physical world is a matter of fact, know a posteriori.
*Skepticism: Hume thought a large variety of things which we think we know are things we cannot really know. Hume was especially skeptical of inductive reasoning, that is, any attempt to generalize from specific instances. Hume's skepticism was based on his empiricism, since the usefulness of induction could not be known a priori or a posteriori.
Hume used both of these theses to attack the metaphysics that was essential to theology in his day. If empiricism was true, it followed that the armchair proofs of the being and attributes of God could be only sophistry and illusion. From skepticism, Hume argued that if we can't be certain that the sun will rise tomorrow (and other knowledge of common life), wew can be even less certain of abstract reasonings. This explains why Hume's Dialogs Concerning Natural Religion spends so much time on the arg't from design and is so dismissive towards the cosmological and ontological arg'ts. This reading is supported by the fact that Cleanthes invokes the scientific theories of Galilleo and Newton as analogous to the design hypothesis, showing that the reasoning involved is not to abstract to be trustworthy.
When Hume jumped from skepticism to sticking to every-day reasoning, he was being grossly fallacious. His skeptical arguments purported to show we have no reason to believe common sense beliefs, could attach no certainty to them, and therefore theological claims couldn't be any less certain. Hume appears to have fleetingly recognized this in his "Letter to a Friend in Edinburgh," written when Hume was about to be denied a teaching position on grounds of irreligion. In it, Hume asks how he could be accused of irreligion when he held the truths of theology are as certain as the "Objects of our Senses." Hume would only admit to this consequence of his view when needed to save his job prospects, he shows no enthusiasm for it elsewhere in his writings, but this does not make the inference less valid.
Any credible philosophy of anything must get rid of global skepticism, and since skepticism of a very serious sort is entailed by Humean empiricism, that also must go. However, we may salvage from Hume his trust in everyday reasonings, even though it cannot be grounded in skepticism. It can be grounded instead in the fact that every-day reasonings are confirmed thousands upon thousands of times in an individual's life. Abstract metaphysics has no such confirmation, and has premises which one side of a dispute claims as obviously true, needing no argument, while the other side sees it as equally obvious that the premises are false. It seems unwise to build much on the assumption that one side in such a dispute is correct, so long as the contrary position would not totally undermine every-day reasoning (as is the case with, say, denials of the law of noncontradition).
Aquinas: Aquinas' approach was to establish the principles of his theology though a series of metaphysical arguments using premises drawn from ancient philosophers, mostly Aristotle, though occasionally others as well.
There are two main objections to his approach, one basic and one deep. The basic objection is that many of his premises were false or at least unsupported. For example, his first-mover argument used Aristotle's doctrine that an infinite regress is impossible. Aquinas says little in favor of this claim and there are plausible counter-arguments; Russell, somewhere, objected that the set of negative numbers provides an example of infinite regress. And even if the prime mover is established, Aquinas must still get through a great series of metaphysical deductions to show the prime mover has the properties normally assigned to God, and along the way Aquinas must use many questionable premises. He took far too much Aristotelian doctrine for granted.
The deep objection is that Aquinas was attempting to use armchair reasoning in areas where such reasoning can tell us nothing. This comes out most clearly in Aquinas' statements on fire, astronomy, and other scientific subjects. He establishes his claims on metaphysical reasonings that look as valid as anything he does in theology, but today we see his science as plainly wrong, and the reason is not better metaphysics but developments in empirical knowledge. Aquinas simply could not know all he wanted to know just by thinking about it.
Kant: Kant's approach was like Aquinas' in its armchair aspect, but differed in Kant's transcendental idealism, which said for the most part we cannot know things in themselves, only things as they appear to us. This protects free will, God, and immortality from conventional attacks, though rules out convention proofs. In the place of normal proofs, Kant argues these basic elements of religious belief must be postulated for the sake of morality.
Aside from the general problems with armchair reasoning shared by Aquinas, Kant's transcendentalism is deeply problematic. The argument for it in the "Aesthetic" part of his critique seems circular. It is not clear that the antinomian arguments in the Dialectic, are really antinomian pairs, and even if so Kant fails to give the sort of rigorous arg't that would be needed to show his radical transcendental solution is the only possible solution. The doctrine is unhelpful for morality, since it prevents us from knowing the consequences of our actions, and in spite of Kant's disdain for consequentialism, his morality requires one to know whether an action will harm a real person or an illusory person. For this and other reasons, the doctrine seems clearly false.
Unlike Hume, Kant does not seem to provide anything salvageable. His moral arg'ts for God and immortality are based on moral principles that are generally problematic and seem out of place in Kant's overall ethical system.
[I ended my answer to this question with a note referring back to my answer to a previous question, here's what I said there...]
Kant thought that if people were not justly rewarded or punished for their right or wrong actions, there would be something irrational about morality. He also thought that we can never have an oblication to sacrifice (either actively or passively) a rational existence, and that we can never have incompatible obligations (the second half of this point is important to emphasize and is somewhat controversial, as some philosophers think there are real moral dilemmas where no choice is right.)
It is not clear whether Kant thought we could know these things or they were merely rational to believe, but the natural theology interpretation will hold that we know them. The next step is to notice that without God and immortality, these things will almost certainly be false. In this life, people do not always get their just deserts, the only way they can gewt them is through immortality. Even then it is unlikely that their existence after death would bring justice unless there were a God managing the affair. Similarly, without immortality we would sometimes have to chose between saving one rational existence and saving another, but with immortality, it is merely a choice between one embodied life and another, which Kant thought acceptable.
Once these premises are established, the argument works like this:
1) The key moral principles above are true
2) If not-"God exists" and/or not-"the soul is immortal," then not-(1).
3) Therefore, God exists and the soul is immortal.
The problematic premise in this argument is premise (1). The very idea of morality is that it is rational to do things not in one's own self-interest, the fact that one will not be justly rewarded does not make moral action irrational. To take the contrary position is especially strange from a Kantian perspective, since Kant's fundamental moral principles involved the need to do one's duty in spite of the consequences and in spite of the fact that the relevant maxims may be being systematically ignored. Similarly, Kant is put in the position of arguing it is acceptable to sacrifice something of great worth for something else of great worth, just not maximum worth for something else of maximum worth. Without that claim immortality does nothing to affect moral dilemmas about loss of life, but Kant does not give clear reasons for the distinction, and without any such justification his position seems simply inconsistent, at lest in the sense of failing to apply a guiding principle in his distinctions.
Tags: philosophy, David+Hume, Thomas+Aquinas, Immanuel Kant