“Don’t be so sure—nobody can be certain of anything.” Bertrand Russell’s gibberish to the contrary notwithstanding, that pronouncement includes itself; therefore, one cannot be sure that one cannot be sure of anything. The pronouncement means that no knowledge of any kind is possible to man, i.e., that man is not conscious. Furthermore, if one tried to accept that catch phrase, one would find that its second part contradicts its first: if nobody can be certain of anything, then everybody can be certain of everything he pleases—since it cannot be refuted, and he can claim he is not certain he is certain (which is the purpose of that notion). - Ayn Rand, "Philosophical Detection", Philosophy: Who Needs It? p14
In the course of making a comment I was reminded of this typical Randian quote. I'd be interested in your views as to the quality of scholarship and argument on display here, given that she is alleged to be the greatest thinker of the past 2000 years. First of all, would Russell really disagree that the statement “Don’t be so sure—nobody can be certain of anything” includes itself? Second, Rand seems to be referring to Russell's work on the liar's paradox and the problems that can arise from self-reference; but "one cannot be sure that one cannot be sure of anything" doesn't seem to be such a paradox - in fact it seems consistent. (A problematic version would perhaps be "One can be sure that one cannot be sure of anything.") And of course this work led to important developments in both mathematics and logic, yet Rand describes it as "gibberish". Third, does it follow that "no knowledge of any kind is possible"? Fourth, does it follow from that that "man is not conscious"? Fifth, isn't the remaining passage pretty close to gibberish itself?