
The Strange Inevitability of Evolution - kirang1989
http://nautil.us/issue/20/creativity/the-strange-inevitability-of-evolution
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woodchuck64
"Evolution need only take a random walk along a web of neutral (or at least
almost neutral) mutations, that, without impairing the fitness of an organism,
surrounds it with very different neighbors: innovative solutions to selective
pressures that are there for the taking when the circumstances compel it."

Wow, that starts to explain the amazing creativity of rapid evolution (like
whale evolution in 10 million years). So how to turn this into software? This
seems like it could be a new class of evolutionary algorithm.

~~~
abecedarius
Gerry Sussman's
[http://groups.csail.mit.edu/mac/users/gjs/6.945/readings/rob...](http://groups.csail.mit.edu/mac/users/gjs/6.945/readings/robust-
systems.pdf) has some related ideas.

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Xcelerate
Wow, this was a very good article (I don't often say that).

I have long had a rather uncomfortable feeling about this idea that many
chance mutations eventually produce some that are close to some objective
function -- for essentially the same reason given in the article. There's just
too many combinatorial possibilities to explore in the rather small time that
the universe has been around (I mean, we're comparing like 10^50 to like
10^(10^(...)) here).

But this makes a lot of sense to me. Essentially what he's saying is that
input sequences (vectors) pass through some kind of surjective mapping into a
lower dimensional space of "networks" (I'll just call them a different space
of vectors).

If I had to guess (and this is purely speculation here), this is probably due
to some symmetry property.

~~~
Retra
A long time ago, I was trying to imagine how complex structures could evolve
out of randomness, I came up with something I called "hinge evolution." Let
the relevant behavior of a system be a function of the contact area between
the two planes of the hinge, and the genetic variation be represented by the
action of hinge. You can vary the hinge angle a lot while only causing minor
shifts in the contact area, but if you _close_ the hinge, there will be a
giant discontinuous spike in the contact area. So I believed it wasn't absurd
to think that things didn't have to evolve in continuous fashion: you could
have 'silent' evolution happening in the background, but when certain
conditions are met, a major shift in structure could happen all at once.

This article elucidates a much better explanation.

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im3w1l
Maybe a reformulation in terms of the familiar can be enlightening:

DNA can spontaneously "refactor" itself, i.e. use vastly different internals
without changing behaviour. For some "implementations", an appropriate change
in behaviour can be much easier than in others.

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hyperpallium
This is _redundancy_ : many different sequences (genotypes) give the same
shape (phenotype). Redundancy can be boring, such as non-significant
whitespace in C code: different spacing compiles the same (and gives the same
behaviour).

It is also _local_ , in that equivalent genotypes are just one step away - add
or remove a space - and you can continue with further steps. So a set of
equivalent genotypes/programs are connected by being adjacent (one "step"
away). [\tangent maybe not all the equivalent genotypes are connected]

But this is _interesting_ redundancy, because some of those equivalent
genotypes are just one step away from dramatically different phenotypes. This
doesn't happen with C whitespace (though maybe it happens with other
equivalent implementations, different names, ways of looping, but I can't
think of an example]

Using the metaphor in the article, one set of equivalent connected genotypes
is like a network of roads, on which you can take steps to move around the
system without penalty, because they are all equivalent and each step is
neutral. Extending the metaphor for the "interesting" aspect, another set of
equivalent connected genotypes with a dramatically different phenotype is like
a railway network. Mostly, the two networks are separate, but sometimes, they
are very close, so that in one step, you switch to another network, like a
railway station. [For correctness, we disallow level crossings, because there
both road and rail would have the same phenotype. We could disallow any
crossings, making it planar, or introduce the third dimension and have bridge
crossings, where the position in 3D is the genotype.]

There would be a great many such networks, with distinct phenotypes.

There would be networks that have no adjacency; but it might still be possible
to reach them by moving to intermediate networks (e.g. travel by car then rail
then bicycle path then footpath etc), provided the phenotypes of those
intermediate networks were neutral or advantageous.

I like _both_ the article's hypotheses: that all complex systems have this
property; or that evolved biological systems only have it because evolution is
faster with it.

2\. The second appeals to me because it helps explain accelerating evolution
by the establishment of platforms: e.g. the body-plan collection of genes may
have taken a long time to come up with, but once it did, body plan diversity
exploded. Though the article complains about the number of body plans
possible, it's dramatically fewer than all possible raw sequences. It's
configuring a body-plan instead of coding it from scratch. Having many
different possibilities is good as it makes it a powerful expressive platform
- perhaps like an algebra or programming language, once it gets complex
enough, it is very powerful. The key quality is that within this configuration
language, the density of "useful" results is higher than without it [e.g. a
random configuration is more likely to be useful than random raw code - the
platform is somehow specialized to its purpose]

Similarly, perhaps this system of RNA with this quality was not the first to
evolve, but several arose... and this is the one that took off.

1\. But maybe all complex systems have it too, provided they have redundancy.
Perhaps, if there are many sets of connected equivalent genotypes, and each
set is very large, there are likely to be many adjacencies between networks?
Note: It's not necessary for _all_ networks to have adjacencies, just enough
of them. You could imagine varying these properties of the system (number and
size of networks, relative to the total space) and come up with parameters
that give "enough" adjacent networks [though I'm not quite sure how to define
"enough".]

My feeling is that getting those parameters good enough by chance might be
pretty rare - something that could take a few billion years over the surface
area of a planet to have reasonable chance at...

~~~
hyperpallium
tl;dr having multiple genotypes for the same phenotype is inevitable if the
genotype space is smaller than the phenotype space; the mapping is not
injective (it's not one-to-one); a projection.

Making this local, where adjacent points map to the same phenotype can be
trivial, e.g. ignoring one dimension of a 10 column row in a database. But an
interesting local mapping seems much rarer: where you can change one dimension
in one step (and still get the same phenotype), then change a different
dimension in the next step, etc, so that the path through space is not just
one dimension varying, but a jagged winding path.

This is important for the "path" (or connected genotypes with the same
phenotype) to have a large surface area, which increases the chance of contact
with the path of another phenotype (and that phenotype has some usefulness).

That's the main problem: that there be adjacency "transfer points" between
useful phenotypes. It seems to me that in the huge exponentially large spaces
we're talking about, they would be very rare, unless the mapping had some
special qualities (which would make sense if the mapping itself had been
selected by evolution - so the "selfish gene" is only secondarily in charge;
the mapping is the primary one - and possibly, mutation strategies, like sex,
and other as-yet undiscovered ones, that might be analogous to factoring or
expanding, so the genotype can change dramatically in one step, but remain
equivalent).

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pcunite
A quote from the article: "You don’t have to be a benighted creationist ..."
Can we please keep these type of articles off HN please? I don’t come here to
be insulted. I have other sites for that!

Sir Isaac Newton was not a simple nor stupid man and he gave honor to the
Creator. Just because science has not figured God out, does not deny His
existence.

A whole lot of reasons for what allowed the Internet, HN, science, and
technology to be where it is at today came out of a nation (silly apparently
to the writer) which put "In God We Trust" on everything.

~~~
solipsism
_Just because science has not figured God out, does not deny His existence._

Science isn't trying to figure god out any more than it's trying to figure
fairies out. Science focuses its efforts on understanding reality.

~~~
Red_Tarsius
Science describes reliable _models_ of reality. Its language is mathematics.

Religion wonders about the ultimate _meaning_ of such models. Its language is
philosophy.

The first religions bundled model and meaning out of necessity. However, post-
Roman Christians were keen logicians and experimenters who laid the foundation
of the modern sciences. They would be ashamed of creationists' shallowness.

~~~
javert
> Science describes reliable models of reality. Its language is mathematics.

That's not right. It's language is... well, language. Including, but not
limited to, mathematics.

> Religion wonders about the ultimate meaning of such models. Its language is
> philosophy.

I don't think this is really being fair to philosophy. I do view religion as a
kind of proto-philosophy. Philosophy is what religion should have been.

~~~
Red_Tarsius
Sorry for the late reply. I like your choice of words, _proto-philosophy_. I
think of religions of the past as proto-philosophy and proto-science (the
world is flat and at the center of the universe, Heaven is structured so and
so, ...). But you're right, my framework does not fully reflect the complexity
of modern faith. Unlike trained priests, the overwhelming majority of
believers don't learn philosophy to challenge their own beliefs.

imho too many people _consume_ religion like painkillers for the big
questions. Without a critical eye, faith becomes anti-philosophy.

------
mschuster91
On a slightly unrelated note, I recommend the new Nightwish album "Endless
Forms Most Beautiful", named after the Darwin quote in the first paragraph.

