A computer is a device that can be instructed to carry out sequences of arithmetic or logical operations automatically via computer programming. Modern computers have the ability to follow generalized sets of operations, called programs. These programs enable computers to perform an extremely wide range of tasks.
Computer science is the study of the theory, experimentation, and engineering that form the basis for the design and use of computers. It is the scientific and practical approach to computation and its applications and the systematic study of the feasibility, structure, expression, and mechanization of the methodical procedures (or algorithms) that underlie the acquisition, representation, processing, storage, communication of, and access to, information. An alternate, more succinct definition of computer science is the study of automating algorithmic processes that scale. A computer scientist specializes in the theory of computation and the design of computational systems. See glossary of computer science.
Alas! A scientific man ought to have no wishes, no affections — a mere heart of stone.
Charles Darwin, in a letter to T.H. Huxley, 9 July 1857, More Letters of Charles Darwin, Francis Darwin and A.C. Seward, editors (1903) volume I, chapter II: "Evolution, 1844-1858", page 98.
Without real experience in using the computer to get useful results the computer science major is apt to know all about the marvelous tool except how to use it. Such a person is a mere technician, skilled in manipulating the tool but with little sense of how and when to use it for its basic purposes.
Richard Hamming, 1968 Turing Award lecture, Journal of the ACM 16 (1), January 1969, p. 6
Software engineering is the part of computer science which is too difficult for the computer scientist.
Friedrich Bauer, "Software Engineering." Information Processing: Proceedings of the IFIP Congress 1971, Ljubljana, Yugoslavia, August 23-28, 1971.