Cooperation is a symmetrical relation: if X cooperates with Y, Y cooperates with X (if that seems unnatural, read 'cooperates' as 'engages in a cooperative venture with'). Depends on, however, is a nonsymmetrical relation: if X depends on Y — in the sense that his getting what he wants out of the venture? depends on Y doing his part — it may or may not be the case that Y depends on X.

DEFINE: Distinguishes the logical symmetry of cooperation from the nonsymmetrical nature of dependence, a key disambiguation for the author's argument.

Diego Gambetta, Trust - Making and Breaking…, loc. 157