I have been doing some hard thinking lately about the origins of life, operating from within the assumptions of biology - and, as always happens, I pretty soon find myself getting perplexed at what I already know but keep on neglecting or forgetting; that biology cannot explain biology.
All biological definitions turn to mush and fuzz - and all biological categories (without which we cannot even begin to do biology) turn out to be unworkable when pushed to the edge.
What is an organism? Nothing to do with a specific set of genes, not really; because there are somatic mutations within the life of the organism - from the moment of its origin, which means that cells differ genetically within the organism - so we are a colony, not a unity.
What is worse, it means that we change identity throughout life.
In trees, for instance, one twig is genetically non-identical with another twig someplace else; and neither are identical with the seed from which the tree grew - the tree is a lineage, not a unity.
And life? It is about metabolism and replication - but metabolism is merely a pattern of processes with interchangeable molecules, and the line drawn around the pattern of processes refers merely to a quantitative concentration of metabolism - there are no sharp lines, but rather a kind of metabolic soup with more activity here and less here.
Replication? Well, at best it is a matter of probabilities and percentages - in nature (as distinct from mathematical or computational simulations) there is no exact replication; and no perfect system for repairing the errors of inexact replication.
So what is the human being? Not the genes, as above. Not the phenotype - the shape, or function - which is constantly changing,
The human being is not even definable by descent - because over evolutionary history things change their nature; how could they not when there is nothing specific carrying the identity. After all, cell culture which was grown from a human lung cancer is related by lineage - and indeed contains most of the genes of the original host - but isn't the human being.
There isn't an answer to these questions! - not from within biology.
Biology is not autonomous - nor are any of the sciences - all exist within a conceptual (metaphysical) framework that is outwith science.
Essential biological concepts like the organism, species, natural selection, life itself - depend upon non-biological definitions of essences or realities or forms.
So I, as an individual person, and as a human being, and a living thing have a non-biological essence - something that biology cannot (and does not) talk about - but takes for granted, denies, ignores and in a thousand ways just leaves-out of consideration.
Natural selection pretends to be some kind of ultimate explanation, but the basic and essential matter of what it is that evolves, how we chop up reality into evolvable units... this is beyond biology, logically prior to biology.
So when I consider the origins of life, it does not take very long, does not take many questions of questions; before I find the question to be formally unanswerable, and I lurch back or veer aside, frustrated by the impossibility - even in principle - of getting any kind of ultimate answer.