The premises of the following argument are plausible, but its conclusion is absurd:

1. The number of (possible) predicates satisfied by two particulars which do not satisfy all the same (possible) predicates is a fixed constant, which equals the number of (possible) predicates satisfied by only one.
2. The number of (possible) predicates satisfied by two particulars is the number of properties they have in common, and the number of (possible) predicates satisfied by only one is the number of properties they have not in common.
3. The degree of resemblance between particulars is a function of the number of properties they have in common and the number of properties they have not in common (perhaps, for example, the ratio of common to uncommon properties).
4. So, the degree of resemblance between two particulars which do not satisfy all the same (possible) predicates, or which do not have all of their properties in common, or which differ from each other, is a fixed constant.

In this paper, I argue that the best way to avoid the conclusion of the argument is not to deny the second premise, but to revise the third.