No disrespect, but I find this comment mind boggling. Disagree with them all you want...it is the people on the Left who tend to be the self-questioners (which is a primary reason they have no power in government anymore).
Well, that's a little misleading, wouldn't you say? In the 1950s, indeed, it was the left-wing that was the self-questioning. But since the 1960s, the left became the orthodoxy in certain circles--esepcially in the American Northeast and in institutes of higher education. Certainly the left-wing professors I have met, and I have met many, are as certain in the correctness of their views as I am certain about anything.
Questioning leftist platitudes is just as hard as questioning, say, christian fundamentalism--if you grow up in a society (such as, say, Ann Arbor or Boston or most American college campuses) where those platitudes are taken as self-evident truths.
As a group, the shining characteristic of conservatives tends to be that they are so certain all the time.
Possibly. But I haven't found left-wingers to be less certain in their beliefs; the acceptance of certain dogmas as self-evident truths that no sane person would possibly question, is just as prevalent on the left as it is on the right. The dogma is "Bush is evil" (for example) instead of "Jesus is Lord" (for example), but is held no less dogmatically and uncritically for all that.
It is just that on the left things tend to be more hypocritical about it: the dogmas are just as dogmatic and held with just as much certainty, but it is pretended that the emotional and uncritical acceptance of left-wing dogmas was reached after some sort of objective, fair analysis and is just held tentatively.
To use an analogy, left-wing dogmatism is like "Intelligent Design", while right-wing dogmatism is like six-day young-earth creationism. Both believe in certain false dogmas for emotional or social reasons, but the "Intelligent Design" movement pretends it's just "objective" and "skeptical".
Richard Dawkins said, quite rightly, that one's religious beliefs are determined, 99% of the time, simply by the accident of birth and upbringing. True. Only he forgot that the same is true, in many cases, for whether one is right-wing or left-wing. Someone growing up in a small town in the south is likely to be right-wing; but someone growing up in, say, Boston or Ann Arbor is no less likely to be left-wing.