Logical fallacies are not the only errors that retard thinking. Conceptual fallacies do, too, and often in subtler, more destructive ways.

Just as logical fallacies violate principles of logic, conceptual fallacies violate those of concept-formation.

The basic principles of concept-formation are presented in Ayn Rand’s Introduction to Objectivist Epistemology (ITOE), which I highly recommend. Fallacies that violate these principles include package-deals, anti-concepts, frozen abstractions, floating abstractions, and stolen concepts. Below are definitions and examples of each, along with…