Surah 36. Yasin, Ayah 36

Lit., "who has created all the pairs out of whatever the earth produces, and out of themselves, and out of that of which they have no knowledge": a reference to the polarity evident in all creation, both animate and inanimate, which expresses itself in the existence of antithetic and yet complementary forces, like the sexuality in human beings, animals and plants, light and darkness, heat and cold, positive and negative magnetism and electricity, the positive and negative charges (protons and electrons) in the structure of the atom, and so forth. (It is to be borne in mind that the noun zawj denotes both "a pair" and "one of a pair", as explained in note [7] on {13:3.}) The mention of "that of which they have no knowledge" evidently relates to things or phenomena not yet understood by man but potentially within the range of his comprehension: hence my interpolation, between brackets, of the words "as yet".

The mystery of sex runs through all creation,-in man, in animal life, in vegetable life, and possibly in other things of which we have no knowledge. Then there are pairs of opposite forces in nature, e.g., positive and negative electricity, etc. The atom itself consists of a positively charged nucleus or proton, surrounded by negatively charged electrons. The constitution of matter itself is thus referred to pairs of opposite energies.