On 30/10/2014 23:40, Matt Mahoney via AGI wrote:
On Wed, Oct 29, 2014 at 8:57 PM, Tim Tyler via AGI <[email protected]> wrote:
One bit per generation with respect to knowing what improves
reproductive fitness. I realize that information can be transmitted to
offspring epigenetically and through language. That's not the same
thing.
A thought experiment should disprove that. Imagine a musical
supervisor allows organisms to reproduce if they play back the
correct Simon sequence [http://en.wikipedia.org/wiki/Simon_%28game%29] -
and they add an extra 5 notes to the correct Simon sequence in each
generation, tell the parents, and allow them to transmit the knowledge
to their offspring (either culturally or via genetic engineering). [...]
This surely qualifies as "knowledge that improves reproductive fitness"
in the specified environment. There isn't much of a limit to how fast
such knowledge can grow.
That's a good point. But we can distinguish the genetic and epigenetic
knowledge here. The genetic knowledge that can only be learned at 1
bit per generation is the knowledge that the agent needs to learn the
Simon sequence and communicate it to its children. The actual sequence
is epigenetic.
Maybe the distinction is not important most of the time. Human
civilization has advanced almost entirely on epigenetic transfer of
knowledge through language. We are genetically not much different than
our ancestors from 10,000 years ago. The crucial genetic knowledge
making civilization possible is the changes in our brains that allowed
us to learn language and communicate. That knowledge had to be learned
at 1 bit per generation.
I think once you allow that adaptive knowledge can accumulate at much
faster rate that the generation time of the dominant species, the
alleged speed limits on evolution disappear. Large slow-reproducing
creatures can form symbiotic relationships with smaller faster-reproducing
ones that can adapt much faster through having shorter generation times.
Our gut bacteria can adapt much faster than we can - allowing us to
adapt quickly to changes in food sources. Our culture can adapt quickly -
since ideas have a short generation time and can reproduce faster than
their human hosts. Brains adapt more rapidly still - since ideas inside brains
and axon spikes are copied even more rapidly and have even shorter
generation times.
These types of copying based on non-nuclear inheritance systems look
set to be accelerated significantly by advances in technology - as
thought moves onto engineered substrates. Note that cultural evolution
is where most of the action is these days. That's the evolution whose
speed we ought to be interested it - since that's increasingly going
to be how evolution will work in the future.
I don't think the idea that slow-reproducing species still have a
low evolutionary speed limit has much merit. Knowledge is a form of
information and can be transferred between media. If we want to
transmit adaptive knowledge into our descendants DNA using genetic
engineering, we can do so - even if that knowledge was originally
acquired by cultural evolution or individual learning.
I think that, if you look to evolutionary theory to support the idea
that evolution is necessarily a slow process, you don't get theoretical
support. Evolution can happen quickly. There's no real speed limit
associated with the theory of evolution - claims to the contrary
notwithstanding. The most obvious limits that come from physics -
for example, the limit to do with the rate at which information
can accumulate in one place before it creates a black hole.
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|im |yler http://timtyler.org/ [email protected] Remove lock to reply.
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