The problem is that there are exactly five regular convex polyhedra (which was mathematically proven already in antiquity). Which means there must exist a fifth element (also known as "quintessence", its Latin name), which would correspond to the fifth Platonic solid, the (12-faced) dodecahedron. In the far future, Luc Besson will imagine the fifth element to take the form of Ms. Milla Jovovich's supple body, but ancient natural philosophers thought it was actually ''aether'', a very subtle substance of which heavenly bodies are made. As ''aether'' does not occur on Earth, we won't be paying any more attention to it.
The remaining four elements may be described by a pair of characteristics: ''hothot /cold cold'' and ''moistmoist /dry dry''. And so, ''earth'' is ''cold'' and ''dry''; ''water'' is also ''cold'', but ''moist''; ''air'' is ''moist'', but ''hot''; and ''fire'' is, obviously, ''hot'' and ''dry''. Every single thing, substance and living being is composed of particles of these four elements in various proportions, which determines each thing's own '''complexion'''. Something which contains, say, more particles of ''fire'' and fewer particles of ''water'' is of ''hot'' and ''dry'' complexion – in a higher or lower degree, depending on the dominance of ''fire'' in the thing's elemental composition.
<mobileonly>[[File:4 żywioły EN.png|thumb|The five elements: earth, water, air, fire and aether. The particles, in the form of regular polyhedra, according to drawings by Johannes Kepler.]]</mobileonly>