And this is what makes Descartes and some others believe that the one pushing it is not the only force making it advance in the water, but that, on the contrary, it has already received a good deal of motion from the tiny particles of the liquid body that surround it and push upon it equally from all sides, and that this motion is only determined by a new motion of the one that pushes it, so that what agitates a body in water could not do so in the void.