96 | SCIENTIFIC AMERICAN | SPECIAL EDITION | WINTER 2022
Maria Maglionico/Eye Em/Getty ImagesOPINIONC AN
SC IENC E
ILLUMINATE
OUR
INNER
DARK
M AT TER?
Neither introspection nor brain scans
can reveal our deepest thoughts
By John Horgan
what’s going on in your head right now? how about ...
now? Or ... now? Answering this question is harder than
you might think. As soon as you pay attention to your
thoughts, you alter them, as surely as you alter an electron’s
course by looking at it. You can’t describe your thoughts the
way you describe, say, the room in which you are reading,
which remains stolidly unaffected by your scrutiny.
William James draws attention to this paradox in “The Stream of Thought,” a
section of The Principles of Psychology. Trying to examine your thoughts through
“introspective analysis,” he writes, is like studying snowflakes by catching them
in your “warm hand,” “seizing a spinning top to catch its motion” or “trying to
turn up the gas quickly enough to see how the darkness looks.”