From: "Nick Arnett" <[EMAIL PROTECTED]> > Huh? Jacob and Monod discovered that genes do turn each other on and off, a > few decades ago. The role of such operations is unclear, but it is a > candidate as a mechanism for cell differentiation and to explain why the > difference in gene numbers between humans and other species isn't as great > as most expected.
Yes, I know this. Just because some genes turn each other on and off does not mean that all genes do so. Transcriptional regulation is useful for activating various cell functions, usually in specialised cases or environments. > > True, classes of neurones will have different transcriptional regulators > > meaning that different genes will be expressed, but there aren't any large > > amounts of on-going dynamic gene switching or modulation going on during > > either a developing or mature brain. > > Are you saying that the mechanisms by which genes give rise to human brains > is well enough understood that we know that such interactions are not > involved? You said "cell signalling," but that's not what I was referring > to. Cell signalling is necessary for neuronal pathfinding in order to create synaptic connections with the 'correct' sort of neurones - so I am talking about genes that give rise to the human brain, and while we do not fully understand how they work, research has indicated a certain stability in the sort of growth factors and cell surface molecules that allow this pathfinding to take place. > > It's also important not to ignore the role of modulating synaptic > > strengths > > as well as the formation and dying off of connections; it's > > thought that the > > strength of synapses is largely responsible for encoding information. > > Encoding information is not the same concept as a data structure. Encoding > is what represents what; the structure is how the encoded data is organized. Who said that the information has to be structed in a physical way? > > I don't think that in order to create an artificial intelligence > > we have to > > fully understand everything that that AI is capable of; it's more than > > possible to understand how to create a human brain and not know > > exactly how > > higher level cognitive functions operate. > > I'm not sure what your point is. Of course it is possible to create a human > brain. The universe did it, with or without intention, depending on your > spiritual beliefs. I thought we were talking about being able to reproduce > its functions sufficiently to create A.I. in a short time frame. And I > can't see how A.I. can be defined without requiring language. I don't think I see what your point is either. I think it's possible for us to create an AI that will be able to learn language; this does not necessarily require us to fully understand language. I might be able to understand the structures in the brain, and how synaptic strengths are regulated, and see how on a basic level information might be processed, and I might be able to reproduced this on a computer, and it might work - but none of this requires an understanding of the higher cognitive functions of the brain. Adrian ======================================================================== Adrian Hon | www.vavatch.co.uk Generation Mars and New Mars | www.genmars.com - www.newmars.com Astrobiology: The Living Universe | www.ibiblio.org/astrobiology
