Just can't get away from that yin-yang, eh? You're quite right,
of course. My friend Dale Carrico was also quick to point this
out to me. My experience has been (and I hope I don't offend anyone
by saying this) that scientist-types tend to be more suspicious of
expectation and its potential to foil perception (e.g., interpretation
of the implications of an empirical experiment), whereas humanist-types
tend to be more permissive of developing new expectations and
allowing them to guide one's perceptions (e.g., a reinterpretation
of an important work of literature).
One of the things I like about the phrase "expectation foils
perception" is that having this expectation about things for a
while eventually enables one to see that expectation also enables
perception. And after rounding this particular epistemological
loop enough times, some find it easier to deploy their filters
deliberately, rather than themselves being deployed by their
built-in filter-reflexes.
-- arkuat