Re: PiP OOL 1 - Origin of Life == Emergence of Biochemistry

On Nov 27, 2:09 pm, "Perplexed in Peoria" <jimmene...@xxxxxxxxxxxxx>
wrote:
This is the first of a planned series of postings in which I will present some
details of my vision of an autotrophic, metabolism-first, membrane-centric
account of abiogenesis. As has been the case with previous planned
posting series, this one may not reach completion if my motivation
peters out, but ... here goes. Blame Howard Hershey for getting me
started.

I am more than happy to take the blame. Believe me, this will be a
*much* more interesting and informative discussion than trying to find
the logic behind Ray's arguments. And unlike that search, one does
not need an electron microscope to even hope to find the logic.

The questions I ask are sincere attempts to clarify, question, and
point out any problems that I can come up with (right or wrong). That
is how it should be. Do not take offense. None is intended. And if
the questions seem wrong-headed or 'dumb' to you, I can live with
that.

I want to begin by taking a fresh look at that old chestnut of a question:
"What is an appropriate definition of life, for purposes of talking about
the origin of life?". I'm going to provide a somewhat 'flip' answer to
this question. "'Life' originates at the same point in time at which
biochemistry emerges from chemistry." That is, if we were observing
the origin of life by using a time machine, we could say that life has
originated at the stage in the process where a chemist studying the
process would say "This ain't just chemistry anymore. What is
happening here is outside my field. We need to call in a biochemist."
Bear with me on this - my answer may grow on you.

The discipline of biochemistry is certainly based on chemistry, and
it reduces to chemistry. But it is not a subset of nor specialization
within chemistry. It is a separate discipline with its own methods
and traditions and with its own notion of what is important in the
phenomenon being studied. Chemistry seeks to develop universal
laws - laws which should be applicable everywhere in the universe.
Biochemistry seeks to find local and contingent laws - it studies
life-as-we-know-it.

But we are, specifically, interested in life-as-we-do-NOT-know-it when
we are discussing the "slippery slope" between abiotic geochemistry
and biochemistry. The slippery slope where, at some point, it becomes
worthwhile to ask "What is the functional relevance of this chemical
reaction or chemical catalyst or chemical *to* a 'living system'?"
That does rather presume the existence of a "living system".

Chemists eschew consideration of 'final cause'.
The molecules in their systems have no function or purpose - they
only have characteristic behaviors. Biochemists embrace a kind
of half-assed final cause or teleology - they are always ready to
ask (and answer) the question of "What is the function of this
molecule, this reaction, this process?"

Actually, they talk about function wrt the potential benefit (defined
as aiding reproduction) that the chemistry, chemical, or catalyst has
*for* the 'living system' in a particular environment.

Biochemists can think in
terms of function only because the systems they study have been
selected by natural selection to have functions.

Which would mean that the definition of life as "A chemical system
capable of evolving (via natural selection?) toward higher
reproductive fitness." might be right. But that means that
'reproduction' (or replication) is a prerequisite. So is whatever
metabolism is needed to produce that 'reproduction' or replication.
Back to the same problem. How to generate a system with those
functions.

Biochemical
systems are a tiny subset of the plethora of possible chemical
systems. Biochemical systems have a contingent evolutionary
history which is an important aspect of the explanation of those
systems. Chemists, for the most part, don't worry about history.

An abiotic molecule exists because the laws of chemistry naturally
lead to its formation. A biochemical molecule exists because its
synthesis serves a function for some organism. Its formation
requires both the laws of chemistry plus the vital interests of
some naturally selected organism. Chemists are interested in
all molecular species. Biochemists are interested mostly in
that rare subset of molecular species which also qualify as
'biochemicals'.

Now, it might be objected that my flip answer just transfers
the problem (of drawing a line of demarkation on a slippery
slope) from one viewpoint to another. There probably wasn't
a clear-cut point in time when you could say with assurance
"Formerly there was no life here; now there is life; life has
originated". And it is still probably the case that you can't say,
"This used to be ordinary chemistry, but now it is biochemistry."
But this objection misses the point.

The reason we want to look at the "What is life?" question is
not to draw a line of demarkation on a slippery slope. It
is instead to provide some illumination of the slope as a whole.

I.e., what steps are necessary to get from a point on the slope where,
by whatever criteria one uses to define 'life', one has gone from a
point at which there is nothing that would be called 'life' to a point
where there exists a 'system' one can at least arguably call a 'living
system'.

And the reason that I suggest that we think about the question
of "What is biochemistry, that we should be mindful of it?" is
because thinking about this question can provide a fresh
perspective on the sequence of steps leading from non-life to
life.

How does it do this? Well, let us simply produce a listing of
the 'laws of biochemistry" and then attempt to address the
question of how and when (ie. in what order) these laws
became laws.

I am not sure there are "laws of biochemistry". But I await to see
what you describe.

In fact, you get a pretty good sketch of a
testable hypothesis of abiogenesis just by listing some laws
that apply to life-as-we-know-it and hypothesizing some
particular order in which these laws actually became laws
in the course of abiogenesis.

I begin the process of doing so in my next posting - "Laws
of Biochemistry".

.

Relevant Pages

  • Re: PiP OOL 1 - Origin of Life == Emergence of Biochemistry
    ... the origin of life by using a time machine, we could say that life has ... process would say "This ain't just chemistry anymore. ... laws - laws which should be applicable everywhere in the universe. ... Biochemistry seeks to find local and contingent laws - it studies ...
    (talk.origins)
  • Re: PiP OOL 1 - Origin of Life == Emergence of Biochemistry
    ... the origin of life by using a time machine, we could say that life has ... process would say "This ain't just chemistry anymore. ... laws - laws which should be applicable everywhere in the universe. ... Biochemistry seeks to find local and contingent laws - it studies ...
    (talk.origins)
  • Re: PiP OOL 1 - Origin of Life == Emergence of Biochemistry
    ... the origin of life by using a time machine, we could say that life has ... process would say "This ain't just chemistry anymore. ... Biochemistry seeks to find local and contingent laws - it studies ... simplest ones can replicate in cell-free systems ...
    (talk.origins)
  • Re: PiP OOL 1 - Origin of Life == Emergence of Biochemistry
    ... "What is an appropriate definition of life, ... process would say "This ain't just chemistry anymore. ... laws - laws which should be applicable everywhere in the universe. ... Biochemistry seeks to find local and contingent laws - it studies ...
    (talk.origins)
  • PiP OOL 1 - Origin of Life == Emergence of Biochemistry
    ... "What is an appropriate definition of life, ... biochemistry emerges from chemistry." ... process would say "This ain't just chemistry anymore. ... laws - laws which should be applicable everywhere in the universe. ...
    (talk.origins)