If it is true that...

Signate matter is not included in the definition of man as man, but signate matter would be included in the definition of Socrates if Socrates had a definition

Then it must be true that...

The essence of man and the essence of Socrates do not differ except as the signate differs from the non-signate

If it is true that...

Signate matter is not included in the definition of man as man, but signate matter would be included in the definition of Socrates if Socrates had a definition

and

The essence of man and the essence of Socrates do not differ except as the signate differs from the non-signate

Then it must be true that...

The essence of a genus and the essence of a species differ as signate from non-signate