Hermann von Helmholtz Quotes

Theory and fact are equally strong and utterly interdependent; one has no meaning without the other. We need theory to organize and interpret facts, even to know what we can or might observe. And we need facts to validate theories and give them substance.

It appears that anything you say about the way that theory and experiment may interact is likely to be correct, and anything you say about the way that theory and experiment must interact is likely to be wrong.

The principle of science, the definition, almost, is the following: The test of all knowledge is experiment. Experiment is the sole judge of scientific "truth." But what is the source of knowledge? Where do the laws that are to be tested come from? Experiment, itself, helps to produce these laws, in the sense that it gives us hints. But also needed is imagination to create from these hints the great generalizations--to guess at the wonderful, simple, but very strange patterns beneath them all, and then to experiment to check again whether we have made the right guess.

In order that the facts obtained by observation and experiment may be capable of being used in furtherance of our exact and solid knowledge, they must be apprehended and analysed according to some Conceptions which, applied for this purpose, give distinct and definite results, such as can be steadily taken hold of and reasoned from.

Theory can leave questions unanswered, but practice has to come up with something.

Nor must we forget that in science there are no final truths.

Observation and theory get on best when they are mixed together, both helping one another in the pursuit of truth. It is a good rule not to put overmuch confidence in a theory until it has been confirmed by observation. I hope I shall not shock the experimental physicists too much if I add that it is also a good rule not to put overmuch confidence in the observational results that are put forward until they have been confirmed by theory.

Science walks forward on two feet, namely theory and experiment.

Epistemology without contact with science becomes an empty scheme. Science without epistemology is-insofar as it is thinkable at all-primitive and muddled.

Science repudiates philosophy. In other words, it has never cared to justify its truth or explain its meaning.

Hope is easy; knowledge is hard. Science is the one domain in which we human beings make a truly heroic effort to counter our innate biases and wishful thinking. Science is the one endeavor in which we have developed a refined methodology for separating what a person hopes is true from what he has good reason to believe.

[Kepler] had to realize clearly that logical-mathematical theoretizing, no matter how lucid, could not guarantee truth by itself; that the most beautiful logical theory means nothing in natural science without comparison with the exactest experience. Without this philosophic attitude, his work would not have been possible.

I never have, above my signature, announced anything that I did not prove first. That is the reason why no statement of mine was ever contradicted, and I do not think it will be, because whenever I publish something I go through it first by experiment, then from experiment I calculate, and when I have the theory and practice meet I announce the results.

It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what his name is if it disagrees with experiment it is wrong. That is all there is to it.

Science walks forward on two feet, namely theory and experiment. Sometimes it is one foot which is put forward first, sometimes the other, but continuous progress is only made by the use of both.

Experiments are mediators between nature and idea.

A theory is a good theory if it satisfies two requirements: it must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.

To test a perfect theory with imperfect instruments did not impress the Greek philosophers as a valid way to gain knowledge.

Science is a collection of successful recipes.

Scientists actively approach the door to knowledge—the boundary of the domain of what we know. We question and explore and we change our views when facts and logic force us to do so. We are confident only in what we can verify through experiments or in what we can deduce from experimentally confirmed hypotheses.

At issue is not only knowledge of the world but our survival as individuals and as a species. All the basic technologies ever invented by humans to feed and protect themselves depend on a relentless commitment to hard-nosed empiricism: you cannot assume that your arrowheads will pierce the hide of a bison or that your raft will float just because the omens are propitious and you have been given supernatural reassurance that they will. You have to be sure.

Any work of science, no matter what its point of departure, cannot become fully convincing until it crosses the boundary between the theoretical and the experimental: Experimentation must give way to argument, and argument must have recourse to experimentation.

Science as such assuredly has no authority, for she can only say what is, not what is not.

Knowledge is the intellectual manipulation of carefully verified observations.

Science is prediction, not explanation.