Collaboration includes collaboration with self and with adversaries

There are also peculiar collaborations with yourself and with your adversaries. Chapter 4 - Documentation describes how you build up a satellite brain in your documentation, to which you sub-contract out the storage of content so that your mind is clear of clutter and thus enabled to put this content into context. This satellite brain is a sort of distillation of your experience as a result of all your past cases.

You are also in a strange collaborative relationship with your adversaries. Criminal and criminologist are in a symbiotic relationship. If there is no crime, then there is no criminology. The good detective has a certain empathy with the criminal. This enables the detective to enter the mind of the criminal and thus anticipate what the criminal will do. I once shocked Watson by saying that I would be a good criminal. Since the criminal is on the edge of society, so the detective must be eccentric - that is, away from the centre. There is no lack of evidence of my eccentricities. They are not the result of pose but simply a lack of concern for social conventions. This empathy with the criminal played a role in a number of cases.

You know my methods in such cases, Watson: I put myself in the man's place, and having first gauged his intelligence, I try to imagine how I should myself have proceeded under the same circumstances [MUSG].
You'll get results, Inspector, by always putting yourself in the other fellow's place, and thinking what you would do yourself [RETI].
I then put myself in the place of Small and looked at it as a man of his capacity would [SIGN].
I have always had an idea that I would have made a highly efficient criminal [CHAS].
There is an eternal shuttle between the minds of the criminal and the detective, as each of them think what the other is thinking that they think. This is one aspect of the genuine complexity of human communication. In this battle of wits between me and Moriarty, this was the point at which I outwitted him.
There are limits, you see, to our friend's intelligence. It would have been a coup-de-maltre had he deduced what I would deduce and acted accordingly [FINA].
I am conscious always of power and design [HOUN].
Let us follow it up in every direction and we can hardly fail to come upon the motive, which shall in turn lead us to the criminal [LION].
My most profound empathy was with my arch-enemy, Professor Moriarty. I described him as consultant in crime, which could very well describe myself [VALL]. Watson used the same metaphor of a spider at the centre of its web to describe us both. This empathy with the enemy was well summarized by one of my criminal opponents: You ain't the law and I ain't the law either --- [3GAB].