Newton's Theory.

This hypothetical substance was flogiston.

Disease Model

Descartes had a dualist substance theory and believed that there were two substances, the mind and the body. Locke also believed that there were spiritual substances and physical substances, but his theory of substance relied on the substratum, a characterless thing that contains the characteristics we observe. Since we cannot observe substance, Locke believed we could not know anything about it.

The generally accepted consensus is that oil is organic. This, however, is only a theory.

An opposing theory is that oil's origin is abiotic. According to this theory, oil is an inorganic substance created deep in the mantle, and is much more plentiful than we believe.

Some scientists say both theories are correct and that there are two different kinds of oil.