Human improvement is a product of many factors, and no power ever yet constituted among mankind includes them all
 John Stuart Mill, Considerations on Representative Government (1861). copy citation

Context

“Partly by intention and partly unconsciously, it is ever striving to make all other things bend to itself, and is not content while there is any thing which makes permanent head against it, any influence not in agreement with its spirit. Yet, if it succeeds in suppressing all rival influences, and moulding every thing after its own model, improvement, in that country, is at an end, and decline commences. Human improvement is a product of many factors, and no power ever yet constituted among mankind includes them all: even the most beneficent power only contains in itself some of the requisites of good, and the remainder, if progress is to continue, must be derived from some other source. No community has ever long continued progressive but while a conflict was going on between the strongest power in the community and some rival power;” source