In his classic political science book, The Open Society and Its Enemies, volume I, The Spell of Plato (1945), Karl Popper examined the application of the critical and rational methods of science to the problems of the open society. In this respect, he made a crucial distinction between the principles of democratic social engineering (what he called "piecemeal social engineering") and Utopian social engineering.
The piecemeal engineer will, accordingly, adopt the method of searching for, and fighting against, the greatest and most urgent evils of society, rather than searching for, and fighting for, its greatest ultimate good.
According to Popper, the difference between "piecemeal social engineering" and "Utopian social engineering" is:
"It is the difference between a reasonable method of improving the lot of man, and a method which, if really tried, may easily lead to an intolerable increase in human suffering.
It is the difference between a method which can be applied at any moment, and a method whose advocacy may easily become a means of continually postponing action until a later date, when conditions are more favorable. And it is also the difference between the only method of improving matters which has so far been really successful, at any time, and in any place, and a method which, wherever it has been tried, has led only to the use of violence in place of reason, and if not to its own abandonment, at any rate to that of its original blueprint -