The science or art of exact reasoning, or of pure and formal thought, or of the laws according to which the processes of pure thinking should be conducted; the science of the formation and application of general notions; the science of generalization, judgment, classification, reasoning, and systematic arrangement; correct reasoning.
Mathematics as an expression of the human mind reflects the active will, the contemplative reason, and the desire for aesthetic perfection. Its basic elements are logic and intuition, analysis and construction, generality and individuality. Richard Courant
Logic will get you from A to B. Imagination will take you everywhere. Albert Einstein
When dealing with people, remember you are not dealing with creatures of logic, but creatures of emotion. Dale Carnegie
Chess helps you to concentrate, improve your logic. It teaches you to play by the rules and take responsibility for your actions, how to problem solve in an uncertain environment. Garry Kasparov
The mind has its own logic but does not often let others in on it. Bernard DeVoto