[T]here's a limit to just how far vents can take you... but... once you've gotten as far as , then you've freed yourself from a fairly small energy f… - Nick Lane

The driving force of is thermodynamics. ...[I]n this context ...the chemical need to react (to dissipate energy) in the same way that water needs to flow downhill.

It could be any of those <nowiki>[</nowiki>sodium, or other ion gradients]. The fact of life on earth is that it tends to use proton gradients, and we know particular environments that do use proton gradients, and the reason I think protons is because , which is to say the proton concentration, can modulate the reactivity of both and . Now sodium concentrations wouldn't do that, but protons, if you've got gas in alkaline fluids, hydrothermal fluids... what you've got coming out of these s, hydrogen is more reactive in alkaline conditions. It really doesn't want to push its electrons onto something else, but if it's in alkaline conditions it pushes its electrons onto something else, and the protons are left behind and they will react immediately with the hydroxide ions to form water, which is thermodynamically very favored, and so it's far more likely to push its electrons onto CO₂ if it's in alkaline solution.

Life as we know it has both, and the people who say s first are in effect saying, "Well, there's plenty of s, there's plenty of RNA. The environment's providing it for free," without worrying themselves too much about what kind of an environment is going to provide all of that for free, and by definition, an environment which is effectively metabolically sophisticated enough to provide s is non-living and therefore not part of the question, so they're just pushing it aside. I would say that the whole metabolic side is needed to give rise to genetic information and nucleotides in an RNA world in the first place, that it would be a dirty RNA world contaminated with s and s, and s and things...