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.
Half of what we know is wrong, the purpose of science is to determine which half.
...for a long time I wanted to become a theologian... now, however, behold how through my efforts God is being debated in astronomy.
I don't believe that the ultimate theory will come by steady work along existing lines. We need something new. We can't predict what that will be or when we will find it because if we knew that, we would have found it already!
Forging differs from hoaxing, inasmuch as in the later the deceit is intended to last for a time, and then be discovered, to the ridicule of those who have credited it; whereas the forger is one who, wishing to acquire a reputation for science, records observations which he has never made.
Light will be thrown on the origin of man and his history.
In big industry new ideas are invited to rear their heads so they can be clobbered at once. The idea department of a big firm is a sort of lab for isolating dangerous viruses.
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