William Kingdon Clifford
mathematician, philosopher, university teacher
Read on Wikipedia1845 – 1879
All Quotes by William Kingdon Clifford
“When an action is once done, it is right or wrong for ever; no accidental failure of its good or evil fruits can possibly alter that.”
“The name philosopher, which meant originally 'lover of wisdom,' has come in some strange way to mean a man who thinks it is his business to explain everything in a certain number of large books. It will be found, I think, that in proportion to his colossal ignorance is the perfection and symmetry of the system which he sets up; because it is so much easier to put an empty room tidy than a full one.”
“I am endeavouring in a general way to explain the laws of double refraction on this hypothesis, but have not yet arrived at any results sufficiently decisive to be communicated.”
“Remember, then, that [scientific thought] is the guide of action; that the truth which it arrives at is not that which we can ideally contemplate without error, but that which we may act upon without fear; and you cannot fail to see that scientific thought is not an accompaniment or condition of human progress, but human progress itself. And for this reason the question what its characters are... is the question of all questions for the human race.”
“No mathematician can give any meaning to language about matter, force, inertia, used in text-books of mechanics.”
“Causation is defined by some modern philosophers as unconditional uniformity of succession, e.g., existence of fire follows from putting a lighted match to the fuel.This idea must be got rid of to understand force. All universally true laws of nature are laws of co-existence, not succession. ...In every case the law at work is seen to be a law of co-existence, not succession.”
“may be roughly described as quantity motion. A body moving at a speed of say twenty an hour, has a certain quantity of motion. If the body goes forty miles an hour there is twice as motion; or if twice as much matter goes twenty miles hour, there is also twice as much motion. Momentum is measured by the quantity of matter moving at a rate mass velocity.”
“Force, defined as above, is not conserved at all. It may appear and disappear; it is continually being created and destroyed. "Conservation of force" is, mathematically speaking, a contradiction in terms.”
“Energy [is of two kinds: 1. Energy of motion; 2. Energy of position].”
“General Results.—Force is a quality of position, definite in magnitude and direction at any point; not constant.2. Energy of position, defined by the statement of the law that the work done in getting from one position to another is the same by whatever path the change of position is made.”
“Is a physical force, such as the attraction of earth, analogous to our "exertion of force" in muscular work? No, for the sensation of muscular effort is complicated. It involves nerve and muscle, which we know not to be present in the simpler cases, e.g., the motion of a stone let fall. To talk of pushing or pulling in such a case is a personification of external nature.”
“It is hardly in human nature that a man should quite accurately gauge the limits of his own insight; but it is the duty of those who profit by his work to consider carefully where he may have been carried beyond it. If we must needs embalm his possible errors along with his solid achievements, and use his authority as an excuse for believing what he cannot have known, we make of his goodness an occasion to sin.”
“The goodness and greatness of a man do not justify us in accepting a belief upon the warrant of his authority, unless there are reasonable grounds for supposing that he knew the truth of what he was saying. And there can be no grounds for supposing that a man knows that which we, without ceasing to be men, could not be supposed to verify.”
“Force is not a fact at all, but an idea embodying what is approximately the fact.”