The total quantity of all the forces capable of work in the whole universe remains eternal and unchanged throughout all their changes. All change in nature amounts to this, that force can change its form and locality, without its quantity being changed. The universe possesses, once for all, a store of force which is not altered by any change of phenomena, can neither be increased nor diminished, and which maintains any change which takes place on it.
Interpretation
The universe's total energy remains constant, despite changes in its form or location.
This quote emphasizes the conservation of energy principle, asserting that while energy can transform from one form to another, the total amount remains unchanged. Hermann Von Helmholtz highlights that the forces at play in the universe are eternal and invariant, underlying all changes and phenomena, suggesting a fundamental law of nature which assures that the sum of energy is preserved regardless of its manifestations.
In practice
In a lecture about physics, you could quote this to explain the conservation of energy.
Isolated facts and experiments have in themselves no value, however great their number may be. They only become valuable in a theoretical or practical point of view when they make us acquainted with the law of a series of uniformly recurring phenomena, or, it may be, only give a negative result showing an incompleteness in our knowledge of such a law, till then held to be perfect.
Black is real sensation, even if it is produced by entire absence of light. The sensation of black is distinctly different from the lack of all sensations.
Whoever, in the pursuit of science, seeks after immediate practical utility, may generally rest assured that he will seek in vain.
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.
The latest authors, like the most ancient, strove to subordinate the phenomena of nature to the laws of mathematics.
I think we're just scratching the surface. One of the most exciting aspects of 23andMe is that we're enabling you to watch a revolution unfold live during your lifetime, and I think that the decoding of the genome, in my opinion, is the most fascinating discovery of our lifetime, and you get to be part of it.
This [climate change] is potentially so dangerous that we have to act strongly. Do we want to play Russian roulette with two bullets or one?
If you want to find out anything from the theoretical physicists about the methods they use, I advise you to stick closely to one principle: don't listen to their words, fix your attention on their deeds. To him who is a discoverer in this field the products of his imagination appear so necessary and natural that he regards them, and would like to have them regarded by others, not as creations of thought but as given realities.
It is the desire for explanations that are at once systematic and controllable by factual evidence that generates science; and it is the organization and classification of knowledge on the basis of explanatory principles that is the distinctive goal of the sciences.
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