<sup>Sorry, but I do not know another place to post this question.</sup>

[Condition of possibility][1] is an important philosophical concept. Naively, this concept could be formally defined this way: 

> $q$ *is a condition of possibility of*
> $p$ **iff** $\neg q$ *implies* $\neg
> p$ 

the latter being equivalent with $p$ *implies* $q$.  When we write $\hookrightarrow$ for *is a condition of possibility of* and $\rightarrow$ for *implies* we get

> $q \hookrightarrow p$ iff $p
> \rightarrow q$.

So, *condition of possibility* is something like *co-implication*.

My question is: While in category theory many concepts and co-concepts are treated as strongly related (= inter-definable) but each in its own right, and while in logic many concepts are treated as strongly related (= inter-definable) but each in its own right: 

> Why wasn't the - philosophically important - concept of *condition
> of possibility* found worthy of being
> named and treated in its own right in (formal) logic?

  [1]: http://scholar.google.de/scholar?hl=de&q=%22conditions+of+possibility%22