REASONING FORWARDS (SYNTHETICALLY) VERSUS REASONING BACKWARDS (ANALYTICALLY)
I have already explained to you that what is out of the common is usually a guide rather than a hindrance. In solving a problem of this sort, the grand thing is to be able to reasoning backwards. That is a very useful accomplishment, and a very easy one, but people do not practise it much. Inthe everyday affairs of day it is more useful to reason forwards, and so the other come to be neglected. There are fifty who can reason synthetically for one who can reason analytically.
Most people, if you describe a train of events to them, will tell you what the result would be. They can put those events together in their minds, and argue from them that something will come to pass. There are few people, however, who, if you told them a result, would be able to evolve from their own inner consciousness what the steps were whichnled up to that result. This power is what I mean when I talk of reasoning backwards, or analytically.
Sherlock Holmes: Chapter XIV, “The Conclusion”, A Study in Scarlet.