I've had some doozies with Remarkl, especially on the social applications of game theory.

In so far as all scientific knowledge is supposed to be tentative, scientists should be openminded about discovering unknown natural effects, but that would be different from being agnostic about the extent of nature. Agnostics are fatalists, whereas scientists are optimistic about conquering and naturalizing the unknown. Scientists deal with the unknown but not so much with the unknowable.