Philosophy / Unit 5 Philosophy 0187 short lesson, about 20 seconds
Numerical and Qualitative Identity
Captions available
The idea
Numerical identity means being one and the same thing; qualitative identity means exact similarity. Personal identity asks about the first, not the second.
In practice
Identical twins are qualitatively alike but numerically two. Yesterday's you and today's you are numerically one, however much you changed.
Where people slip
Conflating the two wrecks every puzzle ahead—"an identical copy" is never automatically you.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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