what relations are, and
what are not, suitable for yielding a valid inference.

In symbols, then, the syllogism becomes:

Major premise: M is P
Minor premise: S is M
Conclusion: Therefore, S is P

{477}

Without confounding logic and psychology in the least, we may take
this symbolic syllogism as a sort of map, on which to trace out the
different exploratory processes that we have already described under
the head of "varieties of reasoning". To do so may make these
different processes stand out more distinctly.

In problem-solution, we start with S, a situation unsolved, i.e.,
without any P. P, when found, will be the solution. We explore the
situation, and find in it M; i.e., we observe that S is M. Now M
recalls our previously acquired knowledge that M is P. Having then
before us the two premises, we perceive that S is P, and are saved.

In rationalization or explanation, we know, to start with, that S is
P, and wish to know _why_ this is so. As before, we explore S, find M,
recall that M is P, and see that S, therefore, is P. Our final
conclusion is, really, that S is P because it is M; that January is
cold because it gets little sunlight.

In application, doubt or verification, we start with the major
premise, M is P, and explore our memories for an S which, being M,
should therefore be P according to our hypothesis. If we find an S
which is _not_ P, then our final conclusion is that the major premise
is false.

Reference to our "map" indicates that there might be several other
varieties of reasoning, and there are, indeed, though they are
scarcely as important as those already mentioned. Reasoning sometimes
starts with the observation of P, which means something that might
prove useful on some future occasion. Your attention is caught by
these prominent words in an advertisement, "$100 a week!" That might
come in handy on some future occasion, and you look further to see how
all that money can be attached to S, yourself on some future occasion.
You soon learn that you have only to secure subscriptions for a
certain magazine, {478} and that income may be yours. P is the money,
and M is the occupation that gives the money, while S is yourself
supposedly entering on this occupation and earning the money. This
type of reasoning is really quite common. If we see a person making a
great success of anything, we try to discover how he does it,
reasoning that if we do the same, we shall also be success