On the last question, your guess is as good as mine. So let's see how many of the others we can get through, starting with the personal question; is it better to be a happy, self-deluding conservative or an unhappy, smart-arsed lefty? It's a question which leads us into the territory of ethical philosophy. It has a number of possible answers, depending on the kind of ethical theory you subscribe to.

Aristotelians would probably select the happy conservative option; this seems to be the best option if your aim is to live the good life as it is described in Aristotle's Nicomachean Ethics. It also fits well with Aristotle's account of the virtues. According to Aristotle, virtue is found at the golden mean between two extremes of vice; courage for example is to be found somewhere on a spectrum that ranges from cowardice at one end to rashness at the other. Both extremes are bad, but somewhere in between we will find the virtue of courage.

To truly flourish we need to live in a way that allows us to exercise not just one virtue, but all the virtues that are appropriate to an Athenian gentleman whose dad just happens to have tutored Alexander the Great. As Elga notes:

... depressed people have been found to have more accurate self-evaluations [than others]. That accuracy probably doesn't help them. There is evidence associating the above sorts of positive illusions with increased happiness, ability to care for others, motivation, persistence, and the capacity for creative, productive work (Taylor and Brown 1988). Furthermore, there is evidence that at least some of the association is causal: that positive illusions help people get by.

A moderate level of self-delusion is conducive to living a good life, both in terms of one's personal welfare and one's capacity for good conduct to others. It might therefore be considered a virtue. So from an Aristotelian point of view rationality lies somewhere between totally tonto at one extreme and pedantically chop-logical at the other. The ideal intelligence is somewhere between total imbecility and too bloody clever by half.

Elga hints at a possible deontological view of the problem. He proposes this norm of rationality:

One ought not have beliefs that go against what one reasonably thinks one's evidence supports.

If we accept this principle, it follows that rationality is the deontological trump that outranks happiness. While a moderate level of self-delusion is conducive to living the good life (whether it as that of a gentleman of ancient Athens or that of a citizen of a 21st century liberal democracy) rationality is more important. Although this begs the question "Why?" it's a position adopted within some recent philosophical traditions (or proto-traditions) such as Objectivism, with its frequent emphasis on the "responsibilities of consciousness" and Jean Paul Sartre's Existentialism, with its equally frequent derision for mauvais-fois, a state of self-delusion very much like that we've been discussing. Objectivists, of course, would reject the unhappy leftist option along with the very happy conservative option in favour of the "rational producer" option or something similar. In any case, the pursuit of personal happiness as a goal becomes questionable as the evidence seems to show that to become happy requires a falling away from rationality and one would become less capable of meeting one's "responsibilities of consciousness".

Assuming that I haven't arbitrarily excluded a substantial tract of middle ground from consideration, it's a tough choice, or it would be, if we really were going to choose our political affiliations on the basis of a choice between greater personal happiness or greater rationality. Right now I can't see any good reason not to continue as a lefty. Some days, it's quite enjoyable.