t would probably be necessary to go further, and
specify which insurrection in Venezuela or in Cuba was intended, before
the average American would be prepared either to affirm or to deny.
Wherever the terms of a proposition are too vague to provoke profitable
discussion they must be narrowed down to a specific case which will draw
forth affirmation and denial.

A common case where the vagueness of the proposition leads to
difficulties in the argument is described in the following passage:

* * * * *

An equally common form of argument, closely allied to the argument by
analogy, and equally vague, is that which is popularly known as the
objection to a thin end of a wedge. We must not do this or that, it is
often said, because if we did we should be logically bound to do
something else which is plainly absurd or wrong. If we once begin to
take a certain course there is no knowing where we shall be able to stop
with any show of consistency; there would be no reason for stopping
anywhere in particular, and we should be led on, step by step, into
action or opinions that we all agree to call undesirable or untrue....

For it must not be forgotten that in all disputes of this kind there are
two parties opposed to each other, and that what divides them is
precisely their lack of agreement on the question what principle is
really involved. Those who see a proposal as a thin end of a wedge
always see the principle as a wider, more inclusive one, than those who
make the proposal; and what gives them freedom so to see it is merely
the fact that it remains indefinite.[5]

As a practical example of this confusion, consider the following extract
from a speech in the United States Senate opposing the popular election
of senators:

* * * * *

Every intelligent student of the present rapid trend toward popular
government must see what would happen when this sentimental bar of the
States being represented by two Senators instead of by the people in the
United States Senate is thrown down. The initiative, the referendum, and
the recall are but symptoms of the times. That the people will have
their way, because they, and they alone, are the government, is the
underlying spirit of our institutions, of our newest State
Constitutions, and of our progressive laws. Skillful agitation seizes
upon every pretext and eagerly grasps and enlarges every opportunity for
appeal to the