No; for I can think of a thing without hearing, seeing, feeling it, etc.

This is because we have memory, which is itself a sensation; it is a
sensation which prolongs itself; to remember is to feel that one has felt;
it is to feel a former sensation which the brain is able to preserve. We
think only by combining current sensations with other current sensations,
or much more often indeed, thanks to memory, by combining current
sensations with older ones, or former sensations with each other. This is
but a fragile basis for knowledge and thought, for sensation is only a
modification of ourselves caused by an external object, and consequently
gives us nothing at all of the external object, and of itself the external
world is eternally unknown to us; but we combine with each other the
illusions that the external world deposits in us through the delusive or
doubtful intermediary of our senses.

When the sensation thus combined with other sensations has become thought,
then ideas begin to exist. They are products of sensation detached from
sensation. They are interassociated by laws that are obscure, yet which can
be vaguely perceived. They awake, so to speak, and call to one another;
every time an idea previously acquired reappears, it is followed by the
thought which accompanied it when it was acquired. In a conversation a
traitor is spoken of. Someone asks what was the value of a piece of silver
in ancient times. This appears incoherent; really it is a natural and
simple association of ideas in which there are few intermediate steps. The
person who listened as the traitor was mentioned thought of Judas, who was
the first traitor of whom he had heard, and of the thirty pieces of silver,
the price of the betrayal by Judas. The association of ideas is more or
less close, more or less loose; it is disconnected in dreams, irregular in
musing, close directly it is dominated and in consequence directed by an