They may prefer to squander their time working out cross-puzzles of mysterious theories built upon the hypotyposistical hypothesis of superannuated guessmen. They still base their empty theories upon the supposition that there exists somewhere and somehow a something called energy which moves matter about from one place to another. But when you understand Penetrability you know beyond any sort of a doubt or guess that the only power that moves matter about in Space is caused by suction and pressure. And from that point on during your education it is easy to learn the cause of sex. Knowledge of Penetrability makes all Natural Laws easy to understand.
Suction is the female of movement and pressure is the male of movement.
There can be no movement without something to move and that is matter. Space with lesser density attracts matter of greater density. So the female of movement, suction, is forever attracting the male of movement, pressure, toward it. All formations are built up by suction which draws into space of lesser density substances of greater density forced there by pressure. It makes no difference whether the formation is an atom or a solar system, the principle is the same.