ABSTRACT
We know very little about a word when we know that it stands for a ‘class concept’. We do not know how it is used. A mistaken view of concepts may lead to a superficial logical analysis, artificially pressing propositions into a common form. This will make it harder to see what the application of logic is, and it obscures the uses of the propositions and of the terms in them. It suggests a false picture of ‘logical relations’ and ‘logical proof’; the notion of the ‘universal validity’ and ‘universal applicability’ of logic, and the especially confusing notion that the principles of logic hold of ‘all propositions’.
