I just became aware of

 Vermeersch, Etienne (1963). Information and Philosophy. Philosophica 1.

Freely available here

http://logica.ugent.be/philosophica/fulltexts/1-4.pdf

a very early attempt to analyse “information” philosophically. There are further references to earlier literature as well, mainly in cybernetic- oriented contexts. All interesting from a historical perspective on the origin of PI.