The first point to make here is that astrology is not directly relevant to this thread. The matching that Leonardo applies between the stars and the saints to construct his painting was purely and solely empirical, based on looking at the sky, understanding the cycle of the year, and embedding that natural pattern secretly in the picture.Movie Nerd wrote:is there a mathematical formula that astrologers use in their work?
Astrology is the claim that the patterns of the cosmos affect life on earth. The way Leonardo has used the cosmos in The Last Supper only requires cosmic effects to the level of the four seasons, since the apostles are grouped in four groups of three from right to left to match the positions of the sun in spring, summer, fall and winter.
The mathematical formula or axiom that unites astrology with science and religion, but is generally very poorly understood, is an extremely old Egyptian Hermetic idea, "as above so below". In its simplest form, this axiom means that everything shares the character of the whole of which it is part.
The earth is part of the cosmos, so our planetary biological identity shares the character of the whole of which we are part. The most basic facts of terrestrial cosmology are the regular pattern's of earth's orbit. Copernicus accurately saw that there are three main patterns, the day, the year, and the wobble of earth's axis.
Leonardo picks out the year as the main pattern. He says the biological identity of life on earth, symbolised by Christ and the twelve, is a part of the whole cosmos, and so is like the shape of the year. So he embeds the year in his painting in order to explain the meaning of the Christ story - as above so below, or thy will be done on earth as in heaven.
This cosmic mirroring principle appears in the Bible in this line from The Lord's Prayer, and in science in the recognition that laws of physics apply equally on earth as in the heavens. The scientific meaning is very basic, but is often not seen due to the magical way this principle has been distorted by both astrology and religion.
A big assumption in The Lord's Prayer is that God's will is not done on earth. Traditionally, this is understood against the theology of the fall from grace into corruption, and the hope that the Second Coming will restore a true relation between earth and heaven. So Leonardo’s depiction of a relation between earth and heaven in The Last Supper keys into this theological idea of a return to a state of grace, a true relation between time and eternity.
These concepts have been severely confused by the magical traditions in astrology, which starts from the same ‘as above so below’ principle which Sir Isaac Newton used to discover the law of gravity but extends it into highly speculative claims about individual personality. Astrology has a mathematical structure, but has not found any evidence that this structure has any causal mechanism and power.