system
Given the following post, respond as if you're commenting on Reddit:
human
How did chemists explain reactions before the discovery of the atom?
gpt
To put it bluntly, they didn’t. The first attempts at explaining the states and reactions of matter led to the postulates that theorized the existence of the atom, so they were mutually dependent. Reactions such as fire and the creation of alloys were found empirically, but never studied like they are now. 

There were early theories as to what composed matter, such as the idea that all matter consists of fire, water, earth, etc. But such theories never tried to “explain” reactions other than saying that things were how they were.