… is from page 644 of the 1988 collection of Lord Acton’s writings (edited by the late J. Rufus Fears), Essays in Religion, Politics, and Morality; specifically, it’s a note drawn from Acton’s extensive papers at Cambridge University; (I can find no date for this passage):
Only in ideas can we see the progress of liberty. It is the great form of progress.
DBx: Yes. And note that Acton’s conception of progress is quite the opposite of the ‘progress’ that is pushed by “Progressives.” The latter ‘progress’ is achieved by that most primitive and mindless of means: coercion initiated against peaceful people.