Richard P. Feynman, Robert B. Leighton, Matthew Sands.
Mainly Mechanics, Radiation, and Heat.
1963
(read but not reviewed)
What do we mean
by "understanding" something? We can imagine that this
complicated array of moving things which constitutes "the world"
is something like a great chess game being played by the gods, and we
are observers of the game. We do not know what the rules of the game
are; all we are allowed to do is to watch the playing. Of
course, if we watch long enough, we may eventually catch on to a few
of the rules. The rules of the game are what we mean by fundamental
physics. Even if we knew every rule, however, we might not be able
to understand why a particular move is made in the game, merely
because it is too complicated and our minds are limited. If you play
chess you must know that it is easy to learn all the rules, and yet it
is often very hard to select the best move or to understand why a
player moves as he does. So it is in nature, only much more so; but we
may be able at least to find all the rules. Actually, we do not have
all the rules now. (Every once in a while something like castling is
going on that we still do not understand.) Aside from not knowing all
of the rules, what we really can explain in terms of those rules is
very limited, because almost all situations are so enormously
complicated that we cannot follow the plays of the game using the
rules, much less tell what is going to happen next. We must,
therefore, limit ourselves to the more basic question of the rules of
the game. If we know the rules, we consider that we "understand"
the world.
