Full Idea
Logic studies the way in which one thing follows from another, in which one thing is compatible with another, contradicts, corroborates or necessitates another, is a special case of another or the nerve of another. And so on.
Gist of Idea
Logic studies consequence, compatibility, contradiction, corroboration, necessitation, grounding....
Source
Gilbert Ryle (Are there propositions? [1930], IV)
Book Reference
Ryle,Gilbert: 'Collected Essays 2 1929-1968' [Routledge 2009], p.22
A Reaction
I presume that 'and so on' would include how one thing proves another. This is quite a nice list, which makes me think a little more widely about the nature of logic (rather than just about inference). Incompatibility isn't a process.