Definitions by contrast:

To do science is to search for repeated patterns, not simply to accumulate facts.

                                Robert H. MacArthur, Geographical Ecology

A modern poet has characterized the personality of art and the impersonality of science as follows: Art is I; Science is We.

           Claude Bernard (1813-1878), Physiologist and "the father of modern experimental medicine"

Poetry is not the proper antithesis to prose, but to science. . . . The proper and immediate object of science is the acquirement, or communication, of truth; the proper and immediate object of poetry is the communication of immediate pleasure.

                                Samuel Taylor Coleridge (1772-1834), Definitions of Poetry

Fiction is about the suspension of disbelief; science is about the suspension of belief.

                                James Porter, UGA Ecology Professor, as quoted by Steve Holland

Religion is a culture of faith; science is a culture of doubt.

                                Richard Feynman, Nobel-prize-winning physicist

Not quite definitions, but critical statements:

As a practicing scientist, I share the credo of my colleagues: I believe that a factual reality exists and that science, though often in an obtuse and erratic manner, can learn about it. Galileo was not shown the instruments of torture in an abstract debate about lunar motion. He had threatened the Church's conventional argument for social and doctrinal stability: the static world order with planets circling about a central earth, priests subordinate to the Pope and serfs to their lord. But the Church soon made its peace with Galileo's cosmology. They had no choice; the earth really does revolve around the sun.

                                Stephen J. Gould, The Mismeasure of Man

The fuel on which science runs is ignorance. Science is like a hungry furnace that must be fed logs from the forests of ignorance that surround us. In the process, the clearing that we call knowledge expands, but the more it expands, the longer its perimeter and the more ignorance comes into view. . . . A true scientist is bored by knowledge; it is the assault on ignorance that motivates him - the mysteries that previous discoveries have revealed. The forest is more interesting than the clearing.

                                                    Matt Ridley, 1999
                   Genome: the autobiography of a species in 23 chapters, p. 271.

There is no philosophical high-road in science, with epistemological signposts. No, we are in a jungle and find our way by trial and error, building our roads behind us as we proceed. We do not find sign-posts at cross-roads, but our own scouts erect them, to help the rest.

                           Max Born (1882-1970), Nobel Prize-winning physicist,
                  quoted in Gerald Holton's Thematic Origins of Scientific Thought

The stumbling way in which even the ablest of the scientists in every generation have had to fight throught thickets of erroneous observations, misleading generalizations, inadequate formulations, and unconscious prejudice is rarely appreciated by those who obtain their scientific knowledge from textbooks

                                James Bryant Conant (1893-1978), Science and Common Sense

I think that we shall have to get accustomed to the idea that we must not look upon science as a "body of knowledge", but rather as a system of hypotheses, or as a system of guesses or anticiptations that in principle cannot be justified, but with which we work as long as they stand up to tests, and of which we are never justified in saying that we know they are "true" . . .

                          Karl R. Popper (1902-1994), The Logic of Scientific Discovery

The real purpose of the scientific method is to make sure Nature hasn't misled you into thinking you know something you don't actually know.

                                Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance

We [scientists] wouldn't know truth if it jumped up and bit us in the ass. We're probably fairly good at recognizing what's false, and that's what science does on a day-to-day basis, but we can't claim to identify truth.

                                Dr. Steven M. Holland, University of Georgia Geology Professor

Science is the most subversive thing that has ever been devised by man. It is a discipline in which the rules of the game require the undermining of that which already exists, in the sense that new knowledge always necessarily crowds out inferior antecedent knowledge. . . . . This is what the patent system is all about. We reward a man for subverting and undermining that which is already known. . . . . Man has a tendency to resist changing his mind. The history of the physical sciences is replete with episode after episode in which the discoveries of science, subversive as they were because they undermined existing knowledge, had a hard time achieving acceptability and respectability. Galileo was forced to recant; Bruno was burned at the stake; and so forth. An interesting thing about the physical sciences is that they did achieve acceptance. Certainly in the more economically advanced areas of the Western World, it has become commonplace to do everything possible to accelerate the undermining of existent knowledge about the physical world. The underdeveloped areas of the world today still live in a pre-Newtonian universe. They are still resistant to anything subversive, anything requiring change; resistant even to the ideas that would change their basic concepts of the physical world.

                           Philip Morris Hauser (1909-), Demographer and Census Expert,
                           as quoted in Theodore Berland's The Scientific Life

Two Illustrative Stories:

A scientist describing for radio broadcast an exciting moment in a baseball game:

Diaz swings a bat, which is apparently made of wood and has no evidence of modifications contrary to baseball rules. He strikes the ball thrown by Johnson, who had not been observed to scratch, scuff, wet, or otherwise modify that ball. The ball is traveling through the air and may pass over the outfield wall on the fly. Yamoto, the rightfielder, heads back to the right field wall, but slows as he reaches the warning track and slumps his shoulders. I believe the ball has passed over the right field wall, and fans seated in the right field bleachers are scrambling as if to retrieve the ball. Meanwhile, the first base umpire has run into right field and is now waving one hand over his head in a circular motion. My own personal observation of the ball's flight, Yamoto's behavior on the warning track, the fans' behavior, and the umpire's signal all lead me to conclude that Diaz has hit a home run and that, if he travels around the bases and touches each base to the satisfaction of the umpires, his team will be credited with a run.

    A carpenter, a school teacher, and scientist were traveling by train through Scotland when they saw a black sheep through the window of the train.
     "Aha," said the carpenter with a smile, "I see that Scottish sheep are black."
     "Hmm," said the school teacher, "You mean that some Scottish sheep are black."
     "No," said the scientist glumly, "All we know is that there is at least one sheep in Scotland, and that at least one side of that one sheep is black."