So why does
an understanding
of what an evolutionary agent is
help us
understand the origin of life,
and in particular
the multiple origins of life.
And it's worth starting
with a case study here
This is Sol Spiegelman
and he was a virologist
and he was interested in the evolution
of very simple viruses.
And the virus he worked with
was called Q Beta Phage.
And this is a very small RNA virus.
And he asked the following question:
What is the minimum genome
the Q Beta has to possess
in order to successfully complete
its life cycle?
But he tricked the virus.
He put a population of viruses
in a test tube,
along with enzymes
that normally
it would have to encode itself.
But he ensured that those enzymes
were always present.
And what he observed,
over multiple replication rounds
of the virus
in this new environment that he created,
was that the virus became
smaller and smaller and smaller,
until it eliminated
all the traces
of the enzyme that now existed
with certainty
in the environment
in which it was evolving.
So we can interpret this experiment
in the following way:
here's a Venn diagram
in one set
of the viral genome V
and another set, the environment,
H, the host.
And the intersection of these two sets,
a gene shared
by the virus and the host
or the virus and its environment,
and what Spiegelman discovered
is that if you make
the environment certain,
then,
the virus minimizes itself.
It throws away all genes it doesn't need
because they're already there.
This is minimalogy.
But he could have performed
an alternative experiment,
and made the environment
very uncertain.
And when environments are very uncertain,
that is, you can't throw things away
because you know they won't be there,
then you have to encode them
intrinsically.
So a good example for us
are vitamins.
With respect to vitamins,
we're minimal,
because we know
they're always there,
we don't have to synthesize them,
right,
but many other genes we can't
be certain we can acquire
from the environment,
so we have to encode them
and transmit them ourselves.
And we call that autonomy.
So these are two different configurations
for an adaptive agent.
Now, many people would call
a virus "non-living"
because it depends on its host
to replicate,
but of course,
we depend on the environment to replicate,
too, because we need vitamins.
So really there is a spectrum
of adaptive agency.
On the one hand,
there are organisms that live
in very certain environments.
And they become simple.
There are other organisms
that live in very uncertain environments,
and they become complex.
They encode more and more
in their genes.
And life spans
this informational spectrum,
from organisms
that encode very little about the world
because they don't need to,
to organisms that encode a great deal
about the world,
because they need to,
to complete their life cycle.
And when you think about it
it in this information theory term,
the way an organism,
or life,
or an agent really is,
is a mechanism
for acquiring adaptive information
about the world that it
propagates forward in time,
then computer viruses,
the block chain,
the Constitution,
and many, many other cultural forms,
are essentially living.
There's nothing special
about
the biochemical example,
a replicated cell,
because a replicating cell
is simply a
somewhat autonomous
informational entity that is
able to propagate itself
forward in time,
just like a Constitution
can.
But like a virus,
the Constitution requires us.
We are
the vitamins
of the Constitution.
And this leads to a very open question
that's worth debating.
On one hand,
we could be fundamentalist.
We could say look,
all of life depends on chemistry,
and so finding the simplest chemistry
that is capable of encoding
adaptive information about the world
is where life really started.
But another possibility say,
well not really, because at any scale
that you can find this basic
set of mechanisms,
you're entitled to call it life.
And you're even
entitled to call it an independent
origin of life.
So by analogy,
someone might say,
"To understand architecture,
to understand Gothic and Renaissance,
or Baroque,
or Rococo architecture,
you need understand quantum mechanics."
And I think that would be foolish,
because all of them of course
ultimately depend on quantum mechanics,
but it's not the differences
in the physics
that explain
the differences in the architecture.
That requires a higher level
of understanding.
And so the pluralist approach
to the multiple origin of life
says that every level,
we need to find those unique mechanisms
that can support
propagation of information.
And there isn't
a "correct,"
most basic level.
It depends on
the question that you're asking
and the variation
that you're trying to explain.