It is not that pearls fetch a high price because men have dived for them; but on the contrary, men have dived for them because they fetch a high price.
Richard WhatelyAs a science, logic institutes an analysis of the process of the mind in reasoning, and investigating the principles on which argumentation is conducted; as an art, it furnishes such rules as may be derived from those principles, for guarding against erroneous deductions.
Richard Whately