While there are many things that we do not know about that era, there are also many other things about which we are completely sure.
For example we know for sure that all the chemical reactions required to assemble the components of a living being required the same amount of energy then as they require now, so either there was a source of energy large enough to enable them, or they were impossible.
Other things may not be completely certain, but they are overwhelmingly plausible, for example if we know that the transition from a more primitive structure to a more complex structure required 5 improbable mutations, we can be pretty sure that there is no chance that all those changes happened simultaneously, but they must have happened in a certain sequence, one by one.
If moreover, there are some causal links between those events, so that some of them cannot happen unless others already happened, then we may be able to determine which was the sequence of those 5 events, with considerable certainty.
While we are unable yet to estimate confidently which of many possible things really happened in the distant past, we can actually exclude with great certainty many other things, about which we can say for sure that they did not happen, because they contradict fundamental laws, like the conservation of energy.
Among these things that certainly did not happen are some previously popular theories about the origin of life, whose authors did not attempt to analyze them in enough detail to see if they are compatible with the known chemistry and physics, e.g. the ancient theory of the "organic soup" or the more recent theory of the "RNA world".
For example we know for sure that all the chemical reactions required to assemble the components of a living being required the same amount of energy then as they require now, so either there was a source of energy large enough to enable them, or they were impossible.
Other things may not be completely certain, but they are overwhelmingly plausible, for example if we know that the transition from a more primitive structure to a more complex structure required 5 improbable mutations, we can be pretty sure that there is no chance that all those changes happened simultaneously, but they must have happened in a certain sequence, one by one.
If moreover, there are some causal links between those events, so that some of them cannot happen unless others already happened, then we may be able to determine which was the sequence of those 5 events, with considerable certainty.
While we are unable yet to estimate confidently which of many possible things really happened in the distant past, we can actually exclude with great certainty many other things, about which we can say for sure that they did not happen, because they contradict fundamental laws, like the conservation of energy.
Among these things that certainly did not happen are some previously popular theories about the origin of life, whose authors did not attempt to analyze them in enough detail to see if they are compatible with the known chemistry and physics, e.g. the ancient theory of the "organic soup" or the more recent theory of the "RNA world".