Re: Human Cloning: The Trade-In Strategy

Hal Finney (
Sun, 23 Feb 1997 16:54:53 -0800

> As I'm sure most of you have already realized, this technology suggests a
> "quick and dirty" approach to transcending the "natural" human lifespan.
> Assuming that the technology for repairing broken neural pathways continues
> to develop as quickly as it has seemed to in the last couple of years, it
> appears that cloning up a replacement body and transplanting the brain is a
> pathway that is almost within reach.

This is a very interesting idea, but I think it's going to take a lot more
research before it becomes possible to hook up the neural connections
between the brain and the new body. There may not even be a one to one
mapping possible, especially if the new body has been quiescent, without
any active brain control. The innervation patterns between the brain and
the muscles and sense organs is presumably at least partially dependent
on a lifetime of usage patterns. The clone won't have the same brain/body
interface as the person.

This is a different problem than repairing broken neural pathways,
because in that case you know that there is a mapping that works, you
just have to induce the nerves to re-grow. Even in that case I doubt
that a complex neural network, like the spinal cord, could be expected
to regrow spontaneously with correct connections.

I am afraid that at best you are looking at years of physical therapy
to learn to use the new body, and since the brain is not as plastic
as an adult as it is when you are young, you will probably never have
completely reliable control or sensation.

And how about the brain cells? Don't they age, with toxic byproducts
building up, DNA damage, etc.? I don't have the impression that brain
tissue is particularly immortal. If not, then even if transplanting
worked it may not help much for extending maximum life span because the
brain will die in a few years anyway.