Ladies and Gentlemen, I urge you therefore to exercise a certain patience with respect to the relations between theory and practice. Such a request may be justified because in a situation like the present — one about which I do not entertain the slightest illusion, and nor would I wish to encourage any illusions in you — whether it will be possible ever again to achieve a valid form of practice may well depend on not demanding that every idea should immediately produce its own legitimating document explaining its own practical use. The situation may well demand instead that we resist the call of practicality with all our might in order ruthlessly to follow through an idea and its logical implications so as to see where it may lead. I would even say that this ruthlessness, the power of resistance that is inherent in the idea itself and that prevents it from letting itself be directly manipulated for any instrumental purposes whatsoever, this theoretical ruthlessness contains — if you will allow me this paradox — a practical element within itself (from here).
Dated, but also plenty to chew on here (via).