Even the way we choose to dole out cash betrays our true motives. Someone with $100 to give away and a world full of worthy causes should choose the worthiest and write the check. We don't. Instead, we give $5 for a LiveStrong bracelet, pledge $25 to Save the Children, another $25 to AIDS research, and so on. But $25 is not going to find a cure for AIDS. Either it's the best cause and deserves the entire $100, or it's not and some other cause does. The scattershot approach simply proves that we're more interested in feeling good than doing good.
Many people are unconvinced by this argument—which I owe to Steven Landsburg—because they are used to diversifying their financial investments (a bit of Google stock and a bit of Exxon, too) and varying their choices (vanilla ice cream AND bananas). But those instincts are selfish: They are not intended to benefit both Google and Exxon, nor both the ice-cream company and the banana growers. With charity, the logic is different, and a truly selfless donor would bite the bullet and put his entire donation behind one cause. That we find that so hard to imagine is just one more indication of how hard it is for us to think ourselves into a truly selfless view of the world.
But there is no sense in which "Someone with $100 to give away and a world full of worthy causes should choose the worthiest and write the check." For one thing, there is no clear sense in which there is a 'worthiest cause'. How would one go about determining that?
For another, if the causes are 'worthy causes', it follows -- quite directly -- that they are worth giving money to, end of story. The fact that one is worthier than another means nothing; if the cause deemed less worthy is still worthy enough to give money to, there is no failure in morality, altruism, or anything else in giving money to it. It's satisficing, not maximizing; and by the very meanings of the terms there is nothing that can be done to try to force the claim that people should only maximize. Worthy is worthy, and there's an end on it.
And the argument doesn't get any better from there. "But $25 is not going to find a cure for AIDS." Neither will $100, so that's a red herring; and since we've already established that we have a whole world full of worthy causes, each of which is worthy of whatever you are able to give, we can't say that you should only give to the worthiest cause; the worthiest cause is most worthy of your money, but that doesn't make any of the others unworthy of it. Think of it in a different light. Person A needs, direly needs, $1000. Person B needs, direly needs, $10000. Clearly Person B's needs are much more severe than Person A's. That may influence your decision to give them money. But the fact that Person B needs the money more than Person A does not mean that Person A does not need the money. To put it in sloganish form, B's needing the money more does not make A need the money less. That is, the fact that B's need is greater does not mean that A's need is not genuine. And it is the same with worthiness of causes. Indeed, in charity worthiness is often direclty a matter of need; all other things being equal, the needier cause is the worthier one. (Needless to say, things often are not quite equal; there are other factors, like efficiency, feasibility, etc., that play an important role. But considering these would only show up the above argument as even more silly, so there's no need to consider them here.)
Finally, the argument says, "The scattershot approach simply proves that we're more interested in feeling good than doing good." It scarcely need be said that nothing in the argument justifies this claim; indeed, nothing is put forward to justify it at all. In the Landsburg article mentioned, Landsburg argues the matter in this way:
You give to charity because you care about the recipients, or you give to charity because it makes you feel good to give. If you care about the recipients, you'll pick the worthiest and "bullet" (concentrate) your efforts. But if you care about your own sense of satisfaction, you'll enjoy pointing to 10 different charities and saying, "I gave to all those!"
But, of course, the fact that I care about the recipients of Charity A doesn't mean I don't care about the recipients of Charity B. Landsburg's error is to assume that my giving to Charity A implies an evaluation of Charity A as worthiest charity, simpliciter; whereas my giving to Charity A implies nothing more than an evaluation that Charity A is a worthy charity. It may in some cases imply that, by some standard of worthiness, Charity A is the worthiest charity at that time according to that standard; but even if we assume this, it does not follow that it will be the worthiest charity at another time according to the standard, nor does it follow that I always use the same standard.
Further, Landsburg's argument involves a false dichotomy between feeling good and caring. Let's take a very obvious case. Suppose you are touring a third world country, and you come across a starving child. And as that starving child looks up at you with his big, starving eyes, you know that nothing would give you greater joy at that moment than to buy that child a meal -- you'd forgo a meal yourself, and much, much more, for it. Now, if Landsburg's dichotomy were legitimate, you have shown yourself not to be a caring person, because you clearly did it in order to feel good about feeding a starving child. But, of course, another way to interpret it would be to say that your feeling good about that action is due to the fact that you care about that child. Let's take a less drastic example closer to home. A single parent takes care of his or her child; he or she also works. Now, if Landsburg is right, this is proof that he or she does not care for the child; for obviously if the parent cared, the parent would 'concentrate' every moment of time for the child. So it follows, according to Landsburg's argument, that the parent really only devotes time to the child because it causes good feelings, rather than because the parent cares for the child. And again, if Landsburg's argument were right, the parent, in going to work, is implicitly evaluating the work as more worthy of his or her time than the child. If you don't think that's parallel enough, make it a division of time between two children rather than between a child and work.
So the argument is nonsense through and through; it is an unrealistic and unreasonable argument. I do, in fact, agree, with part of the intended thrust of the argument, that at least a lot of people give to charity for selfish reasons. Indeed, I know it for a fact; I worked for a summer at André House of Arizona and saw it firsthand in (to name just one of many examples) volunteers who would throw fits if they were put in the kitchen washing dishes instead of on the line dishing out food. It certainly wasn't because the one was less essential to the ministry than the other; it was because they wanted the gratification. I think it's a fairly straightforward fact that a lot of people are like this -- perhaps it's even the case that all of us are like this much of the time. But the above line of reasoning is a horrible argument for this claim. Indeed, it is so bad that every step of it is faulty.
Nicolas at Alpha-Psy, by the way, has a very interesting argument against the above line of reasoning, arguing that justice or fairness may play a role here. I'm a bit skeptical of that (and don't think it's required to deny the suggestion of irrationality, as one can tell from the above argument), but it's an interesting idea, and a sense of fairness does come into play in all sorts of places where you might not originally expect it to be relevant.