St. Anselm believes that the least of our sins puts us in an infinite debt to God and is infinitely bad. Anselm's own argument for this thesis is uses some implicit premises. Here is my best reconstruction:
- (Premise) To sin is to oppose the will of God.
- (Premise) If it is not permissible to do A in order to preserve a good G, then A is at least as bad as the loss of G.
- (Premise) It is not permissible to oppose the will of God "even to preserve the whole of creation", even "if there were more worlds as full of beings as this", and even if "they increased to an infinite extent".
- (Premise) The badness of the loss of the whole of creation if the whole of creation consisted of planets as full of beings as Earth and increased to an infinite extent would be infinite.
- (Premise) If something is at least as bad as an infinite bad, then it's infinitely bad.
- To oppose the will of God is at least as bad as something infinitely bad. (2, 3 and 4)
- To oppose the will of God is infinitely bad. (5 and 6)
- Every sin is infinitely bad. (1 and 7)
- (Premise) To do something infinitely bad puts us in infinite debt.
- Every sin sin is infinitely bad and puts us in infinite debt. (8 and 9)
Probably the most obvious thing to worry about is the conjunction of (2) and (3). Premise (2) appears to be a consequentialist claim. Premise (3), on the other hand, is a premise that the Christian tradition does indeed endorse, but the Christian tradition is not a consequentialist tradition (witness St Augustine on lying and St Paul's insistence that we do not do evil that good might come of it). Thus the argument brings together premises that originate in two competing moral theories, and it is unsurprising that when you do that, you can derive surprising things from their conjunction.
But this is too quick. For there is a lot of plausibility to the consequentialist intuition that Anselm invokes in (2). When one thinks about Augustine and Kant on lying, it "feels right" to say that they value honesty over life. On the side of Kant at least, this is mistaken. Kant's objection to lying isn't that honesty is a greater good than life, because Kant's ethics is not centered on the good (at least not in a way that would make this statement work). So perhaps it is right to affirm the consequentialist intuition in (2) as well as the deontological intuition in (3). And if one does that, then one gets the view that certain actions are infinitely bad.
However, this approach is mistaken. For one does not do justice to both consequentialist and deontological intuitions by supposing that wrong actions are infinitely bad. For consider this situation: If you don't kill an innocent person, a hundred other people will each kill one innocent person. (How can you set this up? One way is statistical. You know that if a certain temptation T is given to people, one percent of people will commit a murder. So you're told that if you don't kill one person, temptation T will be offered to 10,000 people.) Clearly the hundred murders are worse than one murder, and yet it's wrong, according to the deontologist, to kill one innocent person. Moreover, this case is directly a counterexample to (2).
One might try to get out of this counterexample by denying that infinities can be compared. But if one does that, then one can no longer say things that mortal sin is worse than venial sin, and the like. Besides, one does want to be able to compare infinities. If I had a choice between preventing one stranger from committing one murder of a stranger and a hundred strangers from committing one murder apiece, obviously I should prevent the latter.
A different kind of objection to the argument would be that in (2), "at least as bad" should be read as "not less bad" (I am worried about cases of incommensurability). But if one makes the same replacement in (5), it is far from clear whether (5) remains true. For it may be that something is infinitely bad in an aesthetic way (say, an infinitely long bad novel) and something else is finitely bad in an incommensurable way (say, a toothache of finite length); the latter is not less bad than the former, but it does not follow that the latter is infinite.
Nonetheless, even though St Anselm's argument for the infinite badness of sin fails, I think there are alternate ways to make the thesis plausible. But that's a subject for another post (hopefully over the next couple of days).