[Neuroscience] Re: Good book about left brain/right brain

r norman via neur-sci%40net.bio.net (by r_s_norman from _comcast.net)
Wed Oct 24 09:41:01 EST 2007

On Wed, 24 Oct 2007 07:10:41 -0700, Scott H <zinites_page from yahoo.com>

>On Oct 23, 11:50 am, r norman <r_s_norman from _comcast.net> wrote:
>> On Tue, 23 Oct 2007 08:36:39 -0700, Scott H <zinites_p... from yahoo.com>
>> wrote:
>> >That's definitely how it looks from the outside.
>> >I recently brought up the internal asymmetry of the human body on
>> >sci.physics, when I asked if it ultimately depended on the laws of
>> >magnetism, or on some other law of nature that distinguishes between
>> >right and left, as by a cross product. The answer I received was "no,"
>> >but without a convincing explanation.
>> >I've heard that while the left hemisphere can process both affirmative
>> >and negative judgments, the right hemisphere can only process
>> >affirmative ones.
>> >I've also read that while the left medial prefrontal cortex "processes
>> >a personal network related to the self" (www.sciencedaily.com/releases/
>> >2003/11/031111064658.htm), the right medial prefrontal cortex
>> >facilitates our theory of others' minds. In other words, if these
>> >articles are true, then the left medial prefrontal cortex processes
>> >*subjective* information (about ourselves) and the right medial
>> >prefrontal cortex processes *objective* information (about others'
>> >mental states). This is a little ironic considering that many consider
>> >the right hemisphere to be involved in the more subjective aspects of
>> >our thinking. That's why I want a book based on fact and not
>> >speculation.
>> You do have an awful lot of speculation in your thinking.
>> You don't look for "left-hand rules" or "right-hand rules" in physics
>> for the answers that are more reflected in simple developmental
>> processes.
>How do you know that these simple developmental processes aren't in
>turn dependent on properties of the laws of physics? (See below.)
>> During embryonic development, there are genes that
>> determine body axes. Developmental process easily differentiate
>> between anterior and posterior, between dorsal and ventral.  Why would
>> you suspect that they can't also differential between left and right
>> even though most animals have body structures that are largely
>> bilaterally symmetric?
>On the contrary, I admit that developmental processes differentiate
>between right and left.
>More clearly stated, if
>1. A is the property of the laws of physics by which they distinguish
>between left and right (as of, say, the law of magnetism),
>2. B is the ability of the embryo to differentiate between left and
>right, and
>3. C is the chirality of the fully-grown human body,
>then you are telling me that B contributes to C, and that "we don't
>look for A as the answer to C." To this, I respond that A may still
>contribute to B and thereby ultimately contribute to C.

There are people who suggest that physical laws regarding
parity-violation may relate to the fact that biological amino acids
tend to be in l- form while sugars in d- form but even those are
highly suspect and must be regarded as speculative.  Most people think
it to be merely a historical accident.  However suggesting that the
developmental processes of a whole organism to be controlled by such
physical laws is, simply put, ridiculous.  If you want to make such a
suggestion, it is up to you to describe a mechanism by which it could
happen and give some evidence to indicate that your mechanism is,
indeed, at work to the exclusion of alternatives.

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