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41 " If charge were conserved because it was a real particle which moved around it would have a very special property. The total amount of charge in a box might stay the same in two ways. It may be that the charge moves from one place to another within the box. But another possibility is that the charge in one place disappears, and simultaneously charge arises in another place, instantaneously related, and in such a manner that the total charge is never changing. This "
― Richard P. Feynman , The Character of Physical Law
42 " This second possibility for the conservation is of a different kind from the first, in which if a charge disappears in one place and turns up in another something has to travel through the space in between. The second form of charge conservation is called local charge conservation, and is far more detailed than the simple remark that the total charge does not change. So "
43 " I would now like to describe to you an argument, fundamentally due to Einstein, which indicates that if anything is conserved – and in this case I apply it to charge – it must be conserved locally. This "
44 " At first it appears as if the law of conservation is false, but energy has the tendency to hide from us and we need thermometers and other instruments to make sure that it is still there. We "
45 " We find that energy is conserved no matter how complex the process, even when we do not know the detailed laws. "
46 " The first demonstration of the law of conservation of energy was not by a physicist but by a medical man. He demonstrated with rats. If you burn food you can find out how much heat is generated. If you then feed the same amount of food to rats it is converted, with oxygen, into carbon dioxide, in the same way as in burning. When you measure the energy in each case you find out that living creatures do exactly the same as non-living creatures. The law for conservation of energy is as true for life as for other phenomena. Incidentally, "
47 " Therefore I think it necessary to add to the physical laws the hypothesis that in the past the universe was more ordered, in the technical sense, than it is today – I think this is the additional statement that is needed to make sense, and to make an understanding of the irreversibility. "
48 " In the same way if you imagine a part of the world that is closed, and wait long enough, in the accidents of the world the energy, like the water, will be distributed over all of the parts evenly until there is nothing left of one-way-ness, nothing left of the real interest of the world as we experience it. "
49 " The most reasonable possibilities often turn out not to be the situation. If science is to progress, what we need is the ability to experiment, honesty in reporting results – the results must be reported without somebody saying what they would like the results to have been – and finally – an important thing – the intelligence to interpret the results. An "
50 " An important point about this intelligence is that it should not be sure ahead of time what must be. It can be prejudiced, and say ‘That is very unlikely; I don’t like that’. Prejudice is different from absolute certainty. I do not mean absolute prejudice – just bias. As long as you are only biased it does not make any difference, because if your bias is wrong a perpetual accumulation of experiments will perpetually annoy you until they cannot be disregarded any longer. They can only be disregarded if you are absolutely sure ahead of time of some precondition that science has to have. In fact it is necessary for the very existence of science that minds exist which do not allow that nature must satisfy some preconceived conditions, like those of our philosopher. "
51 " frogs are made of the same ‘goup’ as rocks, only in different arrangements. So "
52 " all ordinary phenomena can be explained by the actions and the motions of particles. For "
53 " For example, life itself is supposedly understandable in principle from the movements of atoms, and those atoms are made out of neutrons, protons and electrons. I must immediately say that when we state that we understand it in principle, we only mean that we think that, if we could figure everything out, we would find that there is nothing new in physics which needs to be discovered in order to understand the phenomena of life. Another "
54 " If it were true that the stars could affect the day that it was good to go to the dentist – in America we have that kind of astrology – then physics theory would be proved wrong, because there is no mechanism understandable in principle from the behaviour of particles which would make this work. That "
55 " In general we look for a new law by the following process. First we guess it. Then we compute the consequences of the guess to see what would be implied if this law that we guessed is right. Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment it is wrong. In "
