Nothing can be studied without the knowledge of its properties. Any property which can be found in more than one thing is a common property. Any property which cannot be found in more than one thing is a special property.
The knowledge of the common properties can be applied on more than one thing because a common property can be found in more than one thing. The knowledge of a special property cannot be applied on more than one thing because a special property cannot be found in more than one thing.
No knowledge can be applied on more than one thing if things can have no common property. Is no knowledge applied on more than one thing? No knowledge can be applied by more than one person in the absence of common properties among things. Is no knowledge used by more than person?
Students should learn how to apply knowledge in their studies. A distinction between the knowledge which can be applied on more than one thing and the knowledge which cannot be applied on more than one thing should be made in order to learn how to apply knowledge effectively in studies.
Everyone who proclaims that things can have no common property would not explain: i. how a knowledge can be applied on more than one thing, and ii. how a knowledge can be used by more than one person.