This is a theory known as abiogenesis, which suggests that life arose from non-living matter. The primordial soup is hypothesized to have been a warm, shallow pool of water containing various inorganic molecules, such as methane, ammonia, and hydrogen sulfide. Over time, these molecules reacted with each other, forming more complex organic molecules, such as amino acids and nucleic acids.
It's important to note that the exact nature of the primordial soup and the processes that led to the formation of life are still being debated and researched.