I never understood this line of thinking (it kind of reminds me of the sci-fi trope of the killer virus from outer space). In order for two life forms to be able to interact significantly at a bio-chemical level (let alone eat each other), one would imagine their bio-chemistry would have to be highly compatible. That seems unlikely of lifeforms arising from independent abiogenesis events.

> That seems unlikely of lifeforms arising from independent abiogenesis events.

Not at all, you're presuming there are many different ways life could work, that might not be the case at all. It's entirely possible there's only one or very few possible recipes for life so no matter how many abiogenesis events occur, they produce the same kind of life.

A simple analogy, wood burns, fire is fire, you don't expect every different occurrence of fire in nature to produce a new and incompatible type of fire. Life could be the same, it could be that anywhere carbon based life forms it's basically the same basic recipe and thus biologically compatible with all other forms of carbon based life.

> It's entirely possible there's only one or very few possible recipes for life so no matter how many abiogenesis events occur, they produce the same kind of life.

Presumably this is even MORE likely if the independent lifeforms both emerged in similar physical & chemical environments.

Agreed.

They don't have to eat each other.

https://en.wikipedia.org/wiki/Great_Oxygenation_Event

The vast majority of life on Earth has been wiped out simply because other life created inhospitable conditions for them. Even if multiple events created life, if the wrong life is created, it will die.

Is this necessarily true though? Abiotic synthesis of amino acids is a thing. Might Organism T1 and Organism T2 still be composed of similar basic building blocks, even if they don't share organic ancestry?

Yes, I immediately thought of the final scene of Anathem, when I read GP comment.