Does Sherlock Holmes only solve crimes?

We all know that he does not. Using the same method that he applies in crime detection he does other things too. For example, there is this famous instance that Watson recounts about his visit to the post-office, something that he did on the spur of the moment and about which he had told no one. Exercising his Method Sherlock Holmes knew not only that Watson went to the post-office, but which post-office and what he was doing there.

"... you have been to the Wigmore Street Post-Office this morning, ... when there you dispatched a telegram."

"Right!" said I. "Right on both points! But I confess that I don't see how you arrived at it. It was a sudden impulse upon my part, and I have mentioned it to no one."

"It is simplicity itself," he remarked, chuckling at my surprise--"so absurdly simple that an explanation is superfluous; and yet it may serve to define the limits of observation and of deduction. Observation tells me that you have a little reddish mould adhering to your instep. Just opposite the Wigmore Street Office they have taken up the pavement and thrown up some earth, which lies in such a way that it is difficult to avoid treading in it in entering. The earth is of this peculiar reddish tint which is found, as far as I know, nowhere else in the neighbourhood. So much is observation. The rest is deduction." "How, then, did you deduce the telegram?"

"Why, of course I knew that you had not written a letter, since I sat opposite to you all morning. I see also in your open desk there that you have a sheet of stamps and a thick bundle of postcards. What could you go into the post-office for, then, but to send a wire? Eliminate all other factors, and the one which remains must be the truth."

--The Sign of Four

It is well known also that Sherlock Holmes solves ciphers. In The Dancing Men he was able to decipher a number of secret messages. How did he do it? He did it by using the same method that he used in solving crimes.

But Sherlock Holmes not only solves crimes and deciphers secret messages, he also has a strong interest in some of the sciences (including chemistry but not astronomy). What was he doing in his retirement besides tending bees? 'Of late I have been tempted to look into the problems furnished by nature rather than those more superficial ones for which our artificial state of society is responsible,' he says (The Final Problem). To Sherlock Holmes solving problems presented by nature is no different from solving problems presented by society: we use the same method.

From the above we see that solving crimes, tracking the whereabouts of Dr. Watson, cracking ciphers, engaging in scientific research--all these fall within the province of the detective inasmuch as the same method can be employed in all of them. When we are playing Sherlock Holmes it is not necessary that we be only interested in solving crimes. Indeed, whatever we may be interested in, so long as our interest requires that we employ the same method that Sherlock Holmes employs, we are playing Sherlock Holmes.