"Scientists are always trying to figure out how humans evolved from animals. Well, it's okay to try to understand this, but really, that's not the way to look at human beings. For example, we can't say that because monkeys have so and so many bones and human beings have the same number, they are basically alike. It doesn't change the fact that even in gorillas or orang-utans the head hangs down over the front of the body, no matter how upright they walk. The human head, on the other hand, is supported by the upright body that absorbs pressure.

"Something very remarkable is going on in us there. The minerals we have in us move from the stomach to the head and are deposited there. If there's too much of them, they have to return through the body to be excreted. But something else must also happen to the other substances we have in us after digestion. While they move upward, they undergo another transformation because the upright body partly offsets gravity.

"These substances in part become lighter, and in part they become more concentrated, condensed, and then form sediments. As we often find sediments when we try to dissolve something, so here there are sediments or deposits along the way as these substances move from the stomach to the head. Well, the smallest particles move upward, and on the way they are transformed by the reduced gravity. What happens to them now? These substances originating in our food now turn into a kind of phosphorus. Indeed, the nutrient substances are not merely moving up into our head, but on the way some of the sugar, glycerin, and so forth is transformed into phosphorus

"There are basically two kinds of substances in our head: Salt and other minerals, which are still pretty much as they were before we ingested them with our food, and phosphorus, diffused like air, in fact in a dispersion even finer than that of air. These two, salts and phosphorus, are what we mainly find in our head. The others are present merely to keep us alive. But the two most important substances in the human head are salt and phosphorus.

"As I'll show you later, it is possible to prove that human beings cannot think properly if they don't get the salt and other minerals they need. We need salts and minerals for our thinking. Adding this point to what we have already said about thinking, you can see that human beings are very complicated.

• Salt - Thinking
• Phosphorus - Willing

"If we have too much phosphorus in us, then we get fidgety like a spoiled child, wanting to touch and have everything. Phosphorus is responsible for our willing. If there's too much phosphorus, our will becomes fidgety. When this excessive phosphorus level reaches our head, we will not only be fidgety and nervous (which is due to phosphorus, not to the nerves), but we will actually throw fits and go raving mad. In order to be able to have any will at all, we must have a small amount of phosphorus. However, too much of it makes us insane."

Reference:
Steiner, Rudolf: Lectures to the Workers, The Human Being in Body, Soul and Spirit: Our Relationship to the Earth. Ten Lectures held in Dornach between August 2 and September 30, 1922 for the Workers at the Goetheanun, translated by Joachim Reuter, 1989.
Anthroposophic Press, Hudson, New York, Rudolf Steiner Press, London.
The ten lectures in this book are published in German under the title Die Erkenntnisse des Menschenwesen nach Leib, Seele und Geist - Über frühe Erdzustände (Vol 347 in the collected works).