Feynman

"Now, if the world of nature is made of atoms (and we, too, are made of atoms that obey physical laws)—this obvious distinction between what happens in the past and the future, and this obvious irreversibility of all phenomena—you would think the most likely and obvious interpretation is that some laws—some of the motion laws of the atoms—are going one way, that the atom laws are not such that they can go either way, that there's somewhere in the works some kind of a principle that ooksels only make wooksels, and never vice versa, [...] and that this one—way business of the interactions of things is the thing that makes the whole phenomena of the world seem to go one way.

Yet we haven't found it yet. That is, in all the laws of physics that we've found so far, there doesn't seem to be any distinction of the past and the future, that the moving pictures should work the same way going both ways, and the physicist who looks at it should not laugh—details now to be explained."