R' Yehuda Halevi in the Kuzari 3:37 writes:
"The sage said: This relates to what I told you about engaging in intellectual speculation and arbitrary judgment. Those who engage in intellectual speculation about worship pertaining to the work of heaven (Jer. 7:18, 44:17) exert themselves [far] more than someone who does the work of YHWH (Jer. 48:10) that he is commanded [to do]. For the latter have found rest in their acceptance of tradition on faith, and their souls are tranquil, like someone who goes about freely within the city, without having to be on the alert for any challenge, while the former are like someone who goes about on foot in the desert, who doesn't know what he will meet up with. Therefore, he is armed, alert for battle, schooled in combat, [and] accustomed to it. So don't be surprised by what you see of their resoluteness, and don't be caught off guard by whatever laxity you see on the part of those subject to tradition, I mean, [of course] the Rabbinites. The former sought out a fortress in which they might be secure, while the latter are asleep lying quietly on their bedding, in an ancient, [well]-fortified city."
The king of the Kuzari is confused about the Karaites' apparent religious fervor and intense devotion which apparently contradicts the rabbi's earlier argument that the rabbinic tradition is indispensable to revelation. In the above way Halevi offers a way to understand the Karaites' zeal in relation to the Rabbinates' complacency. Those who are certain they are correct feel no need to be so defensively religious. Only those who rely on frail human rationalities are victim to uncertainties and doubts which lead them to compensate with excess religious zeal.
Now, there is obvious truth here. Who are more versed in the logic and argumentation and evidence and all that goes with being skeptical of traditional Orthodoxy, the skeptics or the Orthodox laity? The skeptics - duh. Who are more comfortable in their place and who care not to question things? The believers. Being tranquil comes with being of unquestioned faith.
It's a rather interesting kind of argument. Those who are most ignorant and less adept argumentatively are considered by Halevi as evidence to the correctness of their beliefs. Since they feel so secure, they don't need to know all that stuff. Therefore, who's opinions are suspect? Those who feel the need to justify their opinions.
I think the whole thing is bogus, of course, since in our modern scientific world we shouldn't care about people's opinions rather only insofar as they can back up their opinions with facts. Nevertheless, it is still an interesting critique on those who are so ready to get into an argument and prove themselves correct on subjects of faith and truth. How sure are they of themselves, really? All they have is their own rationality and intellectual acuity behind them, while the faithful have thousands of years of tradition and the opinions of hundreds (thousands?) of highly respected and intelligent rabbis.
I suppose that the skeptic would feel more sure of himself each time one of the faithful falls below his mighty, unrelenting rationalism. That the believers have no effective way to deal with the skeptic is additional fuel to the skeptic's assertion that the believers are wrong. So he searches out believers to debate and is always ready for argumentative confrontation. He constantly hones his logical skills and familiarizes himself with the relevant information, always ready to best his opponent in the next match. He is armed, alert for battle, schooled in combat, and accustomed to it.
Is being so argumentative a sign of insecurity? Perhaps so.