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Fallacies of Vacuity
Arguments are vacuous when they don’t go anywhere. This happens in two main
ways. Sometimes an argument begins by assuming its conclusion, so the argument
makes no real progress beyond its own assumptions. In other cases, the argument’s
conclusion is empty, so the argument has nowhere in particular to go. Both kinds of
argument are fallacious and vacuous, so we call them fallacies of vacuity. Circular
arguments and arguments that beg the question fall into this category. So do posi-
tions that make themselves immune to criticism by being self-sealing.Circularity
One purpose of arguments is to establish the truth of a claim to someone
who doubts it. In a typical situation, one person, A, makes a claim; another
person, B, raises objections to it; then A tries to find arguments that respond
to the objections and justify the original statement. Schematically:
A asserts that p is true.
B raises objections x, y, and z against it.
A then offers reasons to overcome these objections.
What must A’s responses be like to meet B’s objections? To start with the
simplest case, A cannot meet B’s challenge simply by repeating the original
assertion. If someone is maintaining that terrorists can’t be stopped without
torture, it will not help to offer as a justification for this the very claim that
is in dispute—that terrorists can’t be stopped without torture. The argument
would then look like this:
Terrorists can’t be stopped without torture.
∴ Terrorists can’t be stopped without torture.
This argument is, of course, valid, since the premise cannot be true without
the conclusion being true as well. Furthermore, if the premise is true, then
the argument is also sound. All the same, the argument has no force in this
conversational setting because any objection that B has to the conclusion is
straight off an objection to the premise, since they are identical.97364_ch16_ptg01_323-332.indd 323 15/11/13 11:07 AM
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