Part 5 (continued)
If, then, a man should make this exception and contend that
statements and opinions are capable of admitting contrary
qualities, his contention is unsound. For statements and opinions
are said to have this capacity, not because they themselves
undergo modification, but because this modification occurs in the
case of something else. The truth or falsity of a statement
depends on facts, and not on any power on the part of the
statement itself of admitting contrary qualities. In short, there
is nothing which can alter the nature of statements and opinions.
As, then, no change takes place in themselves, these cannot be
said to be capable of admitting contrary qualities.
But it is by reason of the modification which takes place within
the substance itself that a substance is said to be capable of
admitting contrary qualities; for a substance admits within
itself either disease or health, whiteness or blackness. It is in
this sense that it is said to be capable of admitting contrary
To sum up, it is a distinctive mark of substance, that, while
remaining numerically one and the same, it is capable of
admitting contrary qualities, the modification taking place
through a change in the substance itself.
Let these remarks suffice on the subject of substance.