The defence of atoms might be conducted in this way. One may start from porosity and say something of this sort: All bodies have pores, and therefore so also have all parts of a body: now if this were carried out to infinity, there would ultimately be nothing left of a body but pores. The refutation would be that what remained over would certainly have to be assumed as without pores, and so far as absolutely dense, yet not on that account as consisting of absolutely indivisible particles, atoms; accordingly it would certainly be absolutely incompressible, but not absolutely indivisible. It would therefore be necessary that it should be asserted that the division of a body is only possible by penetrating into its pores; which, however, is entirely unproved. If, however, this is assumed, then we certainly have atoms, i.e., absolutely indivisible bodies, thus bodies of such strong cohesion of their spatial parts that no possible power can separate them: but then one may just as well assume such bodies to be large as small, and an atom might be as big as an ox, if it only would resist all possible attacks upon it.
Imagine two bodies of very different kinds, entirely freed from all pores by compression, as by means of hammering, or by pulverisation; — would their specific gravity then be the same? This would be the criterion of dynamics.
