Does a photon bounce off another photon. Say you had hundreds of watts of laser photons shooting in one direction. Then in the other direction a few stray photons. Will they get deflected off to the side or backwards? If so, then it would explain why the double slit experiment would work. That the photons are constantly bumping into eachother and going seperate ways. That is unless they are not deflected in the up and down axis though.