[Added November 2011]
In his wondeful book Moonwalking with Einstein
Joshua Foer speaks also about Daniel Tammet. This is the famous
autistic savant that has written a book explaining ,among other
things, how he was able to learn the first 22,514 digits of pi.
Joshua Foer attempts to convince the reader that Daniel Tammet is a liar.
Of course there is no doubt that Tammet has Asperger and that he was able
to memorise all these digits (or to perform other extraordinary feats involving memory). What he criticises is the explanation given by Tammet on how he
managed doing it. The reason is very simple: as he very well explains
in his book, there are methods that can enable anyone to do this and these
methods don’t require extraordinary powers like synaesthesia.
According to someone this is a “misstep” in Foer’s book : see for example
this review.
But my opinion is that in this case, it is better to use the Occam razor until
we have more evidence: why should we believe that this accomplishment was possible by extraordinary powers when normal methods suffice?