Human thought results in the diremption of the Cosmos, into Macrocosm and Microcosm. The Macrocosm is what we experience through our senses, the Microcosm what we experience through thought. Through our senses – colour, shape, sound, and so on – we ascertain that something is. But it is through thought that we understand what it is.
In the diagram by Robert Fludd we see the arrangement of the Microcosm. The three Hermetic sciences — Alchemy, Astrology, and Theurgy — address different sections of the diagram as shown in the following chart.
| Microcosm | Macrocosm | |
|---|---|---|
| Thought | Senses | Method of experience |
| Alchemy | Chemistry | Study of the elements. |
| Astrology | Astronomy | Study of stars and planets. |
| Theurgy | Science | Study of angelic hierarchies. |