Similarity can only explain a subset of inductive

inferences

any two objects can share an infinite number of properties; what matters

for induction is the identification of relevant properties. Similarity is used

to explain the notion of relevance, but an independent notion of relevance is

required to explain similarity

All objects have unique properties so it is not clear

how the notion of similarity is relevant

Determining relevant properties requires knowledge of

causation. If we already have knowledge of causation, there is very little work

for similarity to do