All interpretations made by a scientist are hypotheses, and all hypotheses are tentative. They must forever be tested and they must be revised if found to be unsatisfactory. Hence, a change of mind in a scientist, and particularly in a great scientist, is not only not a sign of weakness but rather evidence for continuing attention to the respective problem and an ability to test the hypothesis again and again.

But when we face the great questions about gravitation Does it require time? Is it polar to the 'outside of the universe' or to anything? Has it any reference to electricity? or does it stand on the very foundation of matter–mass or inertia? then we feel the need of tests, whether they be comets or nebulae or laboratory experiments or bold questions as to the truth of received opinions.

I feel that, in a sense, the writer knows nothing any longer. He has no moral stance. He offers the reader the contents of his own head, a set of options and imaginative alternatives. His role is that of a scientist, whether on safari or in his laboratory, faced with an unknown terrain or subject. All he can do is to devise various hypotheses and test them against the facts.

I was working with a Crookes tube covered by a shield of black cardboard. A piece of barium platino-cyanide paper lay on the bench there. I had been passing a current through the tube, and I noticed a peculiar black line across the paper. ...
The effect was one which could only be produced in ordinary parlance by the passage of light. No light could come from the tube because the shield which covered it was impervious to any light known even that of the electric arc. ...
I did not think I investigated. ...
I assumed that the effect must have come from the tube since its character indicated that it could come from nowhere else. ... It seemed at first a new kind of invisible light. It was clearly something new something unrecorded. ...
There is much to do, and I am busy, very busy.[Describing to a journalist the discovery of X-rays that he had made on 8 Nov 1895.]

If three simple questions and one well chosen laboratory test lead to an unambiguous diagnosis, why harry the patient with more?

None of Darwin's particular doctrines will necessarily endure the test of time and trial. Into the melting-pot must they go as often as any man of science deems it fitting. But Darwinism as the touch of nature that makes the whole world kin can hardly pass away.

Science is a mechanism, a way of trying to improve your knowledge of nature. It's a system for testing your thoughts against the universe, and seeing whether they match.

The Big Idea that had been developed in the seventeenth century ... is now known as the scientific method. It says that the way to proceed when investigating how the world works is to first carry out experiments and/or make observations of the natural world. Then, develop hypotheses to explain these observations, and (crucially) use the hypothesis to make predictions about the future outcome of future experiments and/or observations. After comparing the results of those new observations with the predictions of the hypotheses, discard those hypotheses which make false predictions, and retain (at least, for the time being) any hypothesis that makes accurate predictions, elevating it to the status of a theory. Note that a theory can never be proved right. The best that can be said is that it has passed all the tests applied so far.

The comforting, if spurious, precision of laboratory results has the same appeal as the lifebelt to the weak swimmer.

The method of science depends on our attempts to describe the world with simple theories: theories that are complex may become untestable, even if they happen to be true. Science may be described as the art of systematic over-simplification—the art of discerning what we may with advantage omit.

Traditional scientific method has always been at the very best, 20-20 hindsight. It's good for seeing where you've been. It's good for testing the truth of what you think you know, but it can't tell you where you ought to go.

We must trust to nothing but facts: These are presented to us by Nature, and cannot deceive. We ought, in every instance, to submit our reasoning to the test of experiment, and never to search for truth but by the natural road of experiment and observation.