19. The Nature of the Elements

Yesodei HaTorah 4:2

The nature of fire and wind is to ascend upwards from the earth towards the sky. The nature of water and earth is to descend from the sky to the center of the Earth, which is the lowest point there is. There is no consciousness or will in this matter, it's just the nature that God gave them.

Each of the four basic elements has its own characteristics: fire is warm and dry. It is also the lightest of the four basic elements. The nature of wind is warm and moist; water is cold and moist; earth is cold and dry. Earth is the heaviest of the four basic elements. Water is lighter than earth, so water is found above earth. Wind is lighter than water, so the wind hovers above the water. Fire, as we have said, is the lightest of them all.

Everything that exists - people, animals, birds, fish, plants, metal, rocks, etc. - is made up from a combination of the four basic elements. Each one of the elements undergoes changes while being combined with the result that the ultimate combinations do not resemble any of the elements as they are independently. In any combination, there will not be found even one portion of fire, wind, water or earth as they exist on their own; they have all been altered by the combination process.

Everything that is a combination of these four elements will have a combination of the traits of coldness, heat, moisture and dryness. Some things, like creatures that have souls, have more fire attributes, and therefore a higher temperature. Other things, like rocks, have a greater influence from earth, and are therefore very dry. Things that have a greater water influence are moist, etc.

Because of this, one object will by nature be warmer than another that is also warm, and one thing will be drier than another that is also dry. Similarly, in some things only the trait of coldness is noticeable, while in others, only the moisture is noticeable. In some things, both the coldness and dryness are noticeable, or the warmth and dryness are noticeable, or some other combination of traits. The nature of the object will follow the characteristics of the predominant elements in combination with the other elements.

Yesodei HaTorah 4:3

Everything that is made up of the four basic elements will eventually decompose back into them. Some things will break down after just a few days, while others take many years. It is inevitable, however, that everything composed of the four basic elements will ultimately decompose back into them.

Editor’s note: I am not able to explain the Rambam’s science. In Moreh Nevuchim, he is willing to disregard Talmudic dicta (3:14) and even Biblical verses (2:25) in favor of observable science when necessary. Readers are free to assume either that the Rambam was sharing the best science of his day, or that he is describing spiritual rather than physical phenomena.