, Logic (from the Greek λογική logikē) is the formal systematic study of the principle
s of valid inference
and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy
, mathematics
, semantics
, and computer science
. It examines general forms which argument
s may take, which forms are valid, and which are fallacies. In philosophy, the study of logic is applied in most major areas: ontology
, epistemology, ethics
, metaphysics
.
Logic hasn't wholly dispelled the society of witches and prophets and sorcerers and soothsayers.
Logic is a large drawer, containing some useful instruments, and many more that are superfluous. A wise man will look into it for two purposes, to avail himself of those instruments that are really useful, and to admire the ingenuity with which those that are not so, are assorted and arranged.
Logic is logic. That's all I say.
Logic is one thing and commonsense another.
The want of logic annoys. Too much logic bores. Life eludes logic, and everything that logic alone constructs remains artificial and forced.
Logic, like whiskey, loses its beneficial effect when taken in too large quantities.
Metaphysics may be, after all, only the art of being sure of something that is not so, and logic only the art of going wrong with confidence.
Pure logic is the ruin of the spirit.
One cannot use one's logic to explain actions driven by others' logic.