I just received the following request for assessments of IQs of famous
thinkers. Just thought I'd share it. Maybe you could give a better
answer than I did.
>I am Aileen Pariņas, working as a researcher in an advertising agency in
>Manila, Philippines. I am doing a research right now on famous people who
>have very high IQs. I visited your site on Great Thinkers and it has helped
>me a lot. I was just wondering if you know the actual or estimate IQ level
>of these famous personalities (dead or still living) such as Einstein,
>Darwin, Gandhi, Galileo, Da Vinci, Picasso, Siddhartha, etc.
Unfortunately, I do not know of any methods that would help to estimate the IQs of past famous thinkers. Or living - without asking them.
However, as I have spent some time studying intelligence, I would like to make some suggestions. Intelligence is a generic concept covering many abilities related to memorization of various things and performance of different types of perceptive and cognitive tasks. There are as many intellectual skills as there are types of things to memorize and figure out. To be exact, infinitely many radically different intelligent faculties, out of which humans possess a limited number - but still a considerable one, and in various combinations. Intelligence of Picasso is not of the same kind as intelligence of Einstein.
IQ tests assess only rudimentary intelligence skills, and are not applicable to estimating the mental faculties of geniuses. IQ does not even look at people's ability to draw complex generalizations, does not assess creativity at all (!), or qualities like perseverance, willpower, courage, ability to empathize with people, emotional sensitivity, musical talents, perception of color, knowledge of advanced scientific concepts, and very complex problem-solving skills (ability to quickly match simple patterns has little to do with these).
So I think IQ tests should be left for assessing a limited set of mental skills of close-to-normal children. It would take us a while to come up with reasonable numerical estimates for a wide range of complex combinations of high mental skills that define a genius; I personally doubt that a single numeric indicator can make any sense here. Meanwhile, I'd suggest that irrelevance of IQ for assessing skills of geniuses represents an observation worthy of sharing with your readers.
As for the fame, after a certain level of intelligence, a thinkers's fame seems to be a better indicator of the ability of the social masses to recognize this person's talents, than of their own ideas and skills...