If any class closed under isomorphism is definable in sort logic, then sort logic inherits the same structural abstraction that set-theoretic construction already provides, making the contrast with set theory superficial.

?Rate how convincing each reason is below to see the overall strength.

No one has weighed in yet. Be the first to share reasons for or against this statement.

Definable(in logic): Able to be described or specified using a particular set of rules or language—for example, you could 'define' all even numbers using mathematical notation.
closed under isomorphism(as used in logic and mathematics): A group of mathematical objects that stay in the same group whenever you can transform them into each other while keeping their essential structure intact.
contrast with set theory superficial(as used in comparative logic): The differences between sort logic and set theory appear to be surface-level or unimportant, rather than representing a deep fundamental difference.
set-theoretic construction(as used in mathematical logic and foundations): A method of building mathematical objects and systems using set theory, which is based on the idea that everything can be represented as collections of things.

Based on where you are in your exploration