If we look at our own terrestrial life we can observe exactly the same four principles of the seasons. The tiny newly born baby represents the principle of winter. It is like the leafless tree in the winter forest. Its life has come to a standstill since the old age or autumn of its previous terrestrial life until its present more or less dormant state. But after this being's "zone of winter" the mental "spring" sprouts into mental and physical manifestation. The "spring" of this terrestrial life cycle is known by the term "youth". This being's "spring" is also followed by its "summer". The being has reached as far as being able to unfold the entire strength, knowledge and manifestation of its soul. We term this being's mental summer stage "maturity". After this mental summer state the mental autumn stage comes. Here the being's physical unfoldment of life begins to diminish. The organism ages, the being slips slowly towards the end of its terrestrial life cycle and, after a time spent in the spiritual worlds, goes into the mental winter stage of a new terrestrial life. This autumn stage is known by the term "old age". And so the cycles of terrestrial life continue one after another, just as day follows day and year follows year.