@Reconstructo,
Reconstructo;169458 wrote:Right, and it's not new because it's an interesting technique. Say something counter-intuitional and this forces the offended hearer to manifest his reasons. Surely, H knew that in a normal sense we can step in the same river twice. But did they, the less abstract, stop to consider that this river was always different water? The river is the form, and not the water. The river is a concept used to interpret sensation. The nonphilosophical mind doesn't pay attention to this.
imo,
Just as we can identify a predicate with the totality (set) of individuals which satisfies it, we can identify a thing, eg. a river, as the totality (set) of predicates in which it occurs, throughout the duration in which it exists.
The river is not identical to the same river at different times.
The flow of water is different at differing times.
We cannot step into the identical flow of water at different times.
The same river is that river which has the same location, same banks, etc..
The river at T1 is identical to the river at T1.
But, the river at timeT1 is never identical to the river at time T2, even though it is the same river.
Things are all that they have been up to the time considered.
Obviously this set differs at different times.