Now this lesson is quite simply this, that any experience that we have through our senses, whether of sound or of light, or touch, is a vibration. And a vibration has two aspects, one called “on” and the other called “off”. Vibration seems to be propagated in waves and every wave system has crests and it has troughs. And so, life is a system of “now you see it, now you don’t”. And these two aspects always go together.
For example, sound is not pure sound, it is a rapid alternation of sound and silence. And that’s simply the way things are. Only you must remember that the crest and the trough of the wave are inseparable. Nobody ever saw crests without troughs or troughs without crests, just as you don’t encounter, in life, people with fronts but no backs. Just as you don’t encounter a coin that has a heads but no tails.
Just as the heads and tails, backs and fronts, the positives and the negatives are different, they are at the same time One. And one must get used to the notion that different things can be inseparable.