In cell theory, we have cells arise from other existing cell. But the first cell did not arise from existing cell, and that means there are some other condition which allows cell to be formed. I understand the chance of forming the cell without other cells has a low probability, but given it is still possible, does that not contradict the statement itself that you must have other cells to form new cells even ignoring the first cell as a special case?

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    $\begingroup$ Can you please clarify what it is about the standard models of abiogenesis that you do not understand? $\endgroup$
    – jakebeal
    Aug 17 '21 at 14:50
  • $\begingroup$ @jakebeal Thanks - I understand we can create cells from non-living material, but I do not see why we can leave that out in cell theory, and say cells are only created from other existing cells. We can say this is the only way cells are created by living material (ignoring cases which cells arise from non-living material), is from other cells, but then all living materials have cells (from the definition of cell), and so that makes that statement trivial? $\endgroup$
    – Carlos
    Aug 17 '21 at 15:23
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    $\begingroup$ I think this is mostly a confusion of the meaning of "laws" that govern fields like physics and the "laws" that govern biology. Biology tends to stubbornly break any sort of "law" you try to constrain it with (besides those of physics), but that doesn't necessarily make biological "laws" less useful, it's just that we tend to take for granted how things need not be as they are in biology. $\endgroup$
    – Bryan Krause
    Aug 17 '21 at 15:33

Sometimes the probabilities of events are so low, that we can neglect them for all practical purposes. A classical example in thermodynamics: if we have a gas in a container, there is a non-zero probability that all the molecules assemble in one half of this container, while in the other part we have vacuum. It never happens in practice - the probability of such an event is $\propto 2^{-N_A}$, and if one observes a container, one would have to wait for longer than the age of the universe (which is much longer than our lifespan, the existence of the humankind, and the existence of life). Thus, we can confidently treat it as a law, and claim that the sea had never opened in front of Moses.

Same about the acquisition of the cellular membrane: the event might have happened only once in a few billion years, and in very special conditions, which are not at all common nowadays. It is negligible for all practical reasons, to the precision that makes it possible to consider it a law.

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    $\begingroup$ It's also worth noting that existing life will inhibit the emergence of new life, as existing life will tend to quickly eat anything with the potential to become new life. $\endgroup$
    – jakebeal
    Aug 17 '21 at 18:17

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