If we want to abolish capitalism or war, and in doing so not only destroy them but to bring into existence something better, we must begin by understanding them: seeing what the problems are which our economic or international system succeeds in solving, and how the solution of these is related to other problems which it fails to solve. This understanding of the system we set out to supersede is a thing which we must retain throughout the work of superseding it, as a knowledge of the past conditioning our creation of the future. It may be impossible to do this; our hatred of the thing we are destroying may prevent us from understanding it, and we may love it so much that we cannot destroy it unless we are blinded by such hatred. But if that is so, there will once more, as so often in the past, be change but no progress; we shall have lost our hold on one group of problems in our anxiety to solve the next. And we ought by now to realize that no kindly law of nature will save us from the fruits of our ignorance.
R. G. Collingwood
The Idea of History (334)
Some brief comments:
These words were written in the 1930's, thus references to "capitalism and war" seems an obvious choice among systems to supersede. But do not mistake the references a naivete on either topic. Collingwood can probably best be described as a classical--but not uncritical--liberal in politics and economics. His opposition to fascism and Nazism is forcibly argued in his book The New Leviathan.
I find this quote especially applicable to the greatest issue of our time: the political response to climate change, both amelioration and adaptation (we've blown past prevention). Knowing how we've come to this point is indispensable for judging how we should act and what courses we should pursue.
By the way, this is but one part of a paragraph of a brilliant book.