It's a process for enhancing our understanding of the world around us, and for separating nonsense from sense via empirical investigation, logical reasoning, and constant testing.
For surely it is the chemist, not the logician, who will be called upon to tell us whether the following argument is a good one: Without a principled distinction between logical and nonlogical constants, it seems, logic would need to be a kind of universal science: not just a canon for inference, but an encyclopedia.
For the Demarcater, then, understanding the distinction between logical and nonlogical constants is essential for understanding what logic is about.
Borderline cases between logical and nonlogical constants are the following (among others): (1) Higher order quantification, which means quantification not over the individuals belonging to a given universe of discourse, as in first-order logic, but also over sets of individuals and sets of n-tuples of individuals.
But it is the latter, not the former, that we need to sort into logical and nonlogical constants.
The Relativist agrees with the Demarcater that logical consequence must be understood as formal consequence, and so presupposes a distinction between logical and nonlogical constants.
The Deflater agrees with the Demarcater that there is a real distinction between logical and nonlogical constants, and between formally and materially valid arguments.
That does not mean that there is no distinction between logical and nonlogical constants, any more than our inability to give a precise definition of "game" means that there is no difference between games and other activities.
If a distinction that plays an important role in a theory of linguistic competence should turn out to coincide (in large part) with our traditional distinction between logical and nonlogical constants, then this fact would stand in need of explanation.
Someone who found this result intolerable might take it to show either that there must be a principled distinction between logical and nonlogical constants (the Demarcater's conclusion), or that Tarski's definition is misguided (the Debunker's conclusion; see Etchemendy 1990, ch. 9).
As illustrated in Table 10, fault categories are related to Arithmetic, Relational, Conditional, Shift, Logical and Assignment, Variable, Constant, Operator and Statement operators.
