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Dr. Leonard Peikoff originated the fallacy that concepts don’t change. He made his assertion on the grounds that our knowledge is held in the form of concepts and, if they varied, our knowledge would be unstable or incommunicable.

He might as well have argued that our explanations are held in the form of theories and thus theories do not change. Or that there can be no variation of a good design or a valid  idea.

The truth is the opposite. Concepts can be varied and need to be whenever they can be improved or a valuable variant can be developed.

Of course, any given  form of a concept is fixed for a particular context. But that is very different from saying a concept doesn’t change.

This website is dedicated to the idea that concepts are far more sophisticated than Dr. Peikoff will allow and that to declare their immutability is to arrest the dynamism of thought on which human survival depends.

I begin with a demonstration that concepts do change.