To base your answer to Plato on dogs’ genetic similarity, you would also have to “explain” sharks and dolphins as being the same species—the “species” of fish.
Here, too, one search out scientific explanations for how the similarities arose—this time having to do partly with how form is passed along within a species (genetics), and partly with convergent evolutionary pressures that lead sharks and dolphins to both have a streamlined shape, flippers, etc.
Yes, I get that. But, again, Plato didn’t create a category isomorphic to modern knowledge of genetic lines. He created a category based on what Greeks at the time deemed “doglike”. And the answer to that question is purely one of “why do you consider a boundary that includes only those things you call ‘dogs’ worthy of its own label?” Only later, as humans gained more knowledge, could they ask more complex questions about organisms that require knowledge of genetics, selection pressures, and convergent evolution. But the Greeks were not then at that point.
Also, explanations having to do with how humans deem something doglike are scientific.
Edit: To make the point clearer, consider ansewring Plato by saying “dogs are similar because genes determine what an animal looks like, animals reproduce by passing genes, and all dogs have similar genes”. Such an answer would be wrong (uninformative) because it uses the premise “animals you give the same label to are similar because they have genes proportionally similar”. This model is wrong, as it requires (per my above comment) you to also tell Plato that “shark-fish and dolphin-fish are similar because genes determine what an animal looks like, animals reproduce by passing genes, and all fish have similar genes.”
Here, too, one search out scientific explanations for how the similarities arose—this time having to do partly with how form is passed along within a species (genetics), and partly with convergent evolutionary pressures that lead sharks and dolphins to both have a streamlined shape, flippers, etc.
Yes, I get that. But, again, Plato didn’t create a category isomorphic to modern knowledge of genetic lines. He created a category based on what Greeks at the time deemed “doglike”. And the answer to that question is purely one of “why do you consider a boundary that includes only those things you call ‘dogs’ worthy of its own label?” Only later, as humans gained more knowledge, could they ask more complex questions about organisms that require knowledge of genetics, selection pressures, and convergent evolution. But the Greeks were not then at that point.
Also, explanations having to do with how humans deem something doglike are scientific.
Edit: To make the point clearer, consider ansewring Plato by saying “dogs are similar because genes determine what an animal looks like, animals reproduce by passing genes, and all dogs have similar genes”. Such an answer would be wrong (uninformative) because it uses the premise “animals you give the same label to are similar because they have genes proportionally similar”. This model is wrong, as it requires (per my above comment) you to also tell Plato that “shark-fish and dolphin-fish are similar because genes determine what an animal looks like, animals reproduce by passing genes, and all fish have similar genes.”