Unidentical

Two mental states, M 1 and M 2, are thus narrowly (type-) unidentical if and only if M 1 is a mental state about A and M 2 is a mental state about B, when A ≠ B or A = B but there is no mental state about this co-referentiality.

It was the Amazing Dennis “Full” Price, another of our licensed operatives. He and his brother, David, known as Half Price, were famous as the most unidentical twins on record. David was tall and thin and would sway in a high wind, while Dennis was short and squat like a giant pink pumpkin.