The Hound of the Baskervilles

One of the novel's primary themes is the conflict between rationalism and superstition. Much about the hound case suggest occult explanations, but Holmes steadfastly refuses to consider such possibilities. It is easy to understand why many turn to such explanations. It is not only that the people of the moor are primitive, tied to a folk religion. It is also that there is so little evidence with which to construct a rational explanation, other than the myth of the hound. Even a man of science - Dr. Mortimer - is driven to consider such occult possibilities.

But Holmes represents the power of the intellect: he possesses sound reasoning abilities and sharp observation skills. He tends to approach problems from a scientific standpoint, avoiding religion or superstition as causes. Instead of turning to implausible possibilities, Holmes seeks for clues where others have not looked. The idea seems to be that there is always a rational explanation; the evidence just might not always be easily observable. But the first step towards finding that evidence is to prize the power of the rational mind, and refuse to consider irrational possibilities.