Biology textbooks frequently suggest that given enough time under the right condition, the right organic molecules can evolve into the building blocks of life. Eventually these building blocks will self=assemble into early life which will eventually evolve into people.
The major assertion in this scenario is that life will emerge through purely natural processes without any intelligent intervention or creative act. Put another way, the central claim of biology is that life is almost inevitable given the right circumstances.
There is nothing more involved than just the simple laws of chemistry and physics – there is no need for any intelligent intervention. The random distribution of molecules and chemical reactions over time and space of the huge universe will eventually produce the building blocks of life which will then self-assemble into life itself.
The whole idea that life arose from non-life at least once in the history of the universe is the concept known as abiogenesis.
It is obviously impossible for the scientist to travel back in time to personally examine the creation of life. The scientist must infer from what we can evaluate now about conditions that were present early in earth’s history, and then determine a likely scenario for how life began. This is the same type of evaluative process that occurs in other sciences such as paleontology, archaeology, or even forensic medicine.
We can evaluate the most likely circumstances concerning a remote event from the information that we currently have about that event. Chemists have learned a lot about chemical reactions and how they form new molecules, and then how these molecules are destroyed over time. It is from this knowledge that basic assumptions can be made concerning the origin of life.
The central assumption of abiogenesis is that it must be true; even if our current understanding of biology is unable to explain how life could originate through purely natural causes, some purely natural cause must have caused it. The only problem is to determine that natural cause – there is no room for a metaphysical cause and certainly no concept of intelligent design (or a Designer).
To the casual observer, it would seem self-evident that science should follow any evidence wherever it might lead – but this is not the case.