produced by one's senses.
It is an interesting fact about sensations that one naturally
has them, and that very little or no learning is involved in the
abilities of seeing, hearing, smelling, feeling etc., though there seems
to be quite a lot of fine-tuning of these abilities in one's early years
(and sometimes also in one's later years when acquiring special skills).
A related interesting fact about sensations is that people usually
easily come to agree about them (it usually takes little discussion to
decide whether or not there is a hippopotamus in the room, nor whether
the hippopotamus in the zoo is really yellow or not), and normally
attribute the capacity of having them to each other - even though (apart
from ESP) no person can have the experiences of other persons. (See:
Other minds and
In any case, the capacity for having sensations of various definite
kinds, related to sense-organs, is one of the foundations of
knowledge and the possibilities of human