4. Ideas fade in the memory.
Concerning the several degrees of lasting, wherewith ideas are imprinted on the
memory, we may observe,--that some of them have been produced in the understanding by an object affecting
the senses once only, and no more than once; others, that have more than once offered themselves to the senses,
have yet been little taken notice of: the mind, either heedless, as in children, or otherwise employed, as in men
intent only on one thing; not setting the stamp deep into itself. And in some, where they are set on with care and
repeated impressions, either through the temper of the body, or some other fault, the memory is very weak. In all
these cases, ideas in the mind quickly fade, and often vanish quite out of the understanding, leaving no more
footsteps or remaining characters of themselves than shadows do flying over fields of corn, and the mind is as
void of them as if they had never been there.
