Necessary conditions for consciousness

Jeffrey Kazuo Yoshimi yoshimi at grad-ea-6.oac.uci.edu
Mon Feb 5 16:41:52 EST 2001


Hi,

I am a philosopher studying consciousness and the brain, which tends to be
sort of annoying (the experimentalists do all this hard work and then
arm-chair cowboys speculate about it and get it wrong in the process) but
I appeal to your patience and ask some questions.

Assume that for a brain to produce conscious experience, it is necessary
that some set of conditions c1..cn obtain.  Take away any ci from a
consciousness-producing brain, and the brain in question no longer
produces consciousness.  Of course we could not prove that any such
condition is necessary, but I'm not looking for proof, just empirical
hypotheses about what such conditions might be.

I would guess that some such conditions might be:

c1: At least some number n of neurons must be firing (can there be a
conscious-brain where no neurons fired?)

c2: These n neurons must fire above some threshold. (do m > n barely
active neurons give rise to consciousness?)

And so forth.

Perhaps this way of thinking about the question is wrong.  If so, why?  If
not, are there speculations on how many neurons are minimal for
consciousness, and /or what threshold must be surpassed?  Are there other
hypothesized conditions ci?  Perhaps glial cells do something that is
essential, perhaps a medium which allows an electrical field surpassing
the local field is essential (i.e. imagine a brain with firing neurons but
silicon replacements for the glial cells or some sort of insulation
surrounding all the neurons).

So I descend into the philosopher's most dangerous luxury--thought
experiment.

If any of this stuff is answered in any existing text (I was thinking
anesthesiology textbooks might be useful), or is speculated about in any
way, or is completely wrongheaded, I'd like to hear about it.

Thanks for your patience!

Jeff Yoshimi
UC Irvine

PS: Another good question, to me.  Could sufficient conditions s1..sn be
specified such that any brain meeting them produces consciousness?  This
would be like a recipe for a consciousness-producing brain (is
"consciousness-producing" an acceptable phrase?) which would encompass
the necessary conditions above.









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