A study of the history of opinion is a necessary preliminary to the emancipation of the mind. John Maynard Keynes
Instead of looking on discussion as a stumbling block in the way of action, we think it an indispensable preliminary to any wise action at all. Pericles
An ethic gone wrong is an essential preliminary to the sweat shop or the concentration camp and the death march. Simon Blackburn
The manner in which a paradoxer will show himself, as to sense or nonsense, will not depend upon what he maintains, but upon whether he has or has not made a sufficient knowledge of what has been done by others, especially as to the mode of doing it, a preliminary to inventing knowledge for himself. Augustus De Morgan
I think we may safely say that the studies preliminary to the construction of a great theory should be at least as deliberate and thorough as those that are preliminary to the building of a dwelling-house. Charles Sanders Peirce
DUEL, n. A formal ceremony preliminary to reconciliation of two enemies. Great skill is necessary to its satisfactory observance if awkwardly performed ... deplorable consequences sometimes ensue. A long time ago a man lost his life. Ambrose Bierce