  Contrary qualities are found in us “as the same thing.”  But they are the same by virtue of one thing changing around to another. We are asleep and we wake up; we are awake and we go to sleep. Thus sleep and waking are both found in us, but not at the same time or in the same respect. Indeed, if sleeping and waking were identical, there would be no change as required by the second sentence. Contraries are the same by virtue of constituting a system of connections: alive-dead, waking-sleeping, young-old. Subjects do not possess incompatible properties at the same time, but at different times.