Newsgroups: comp.ai.philosophy
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!news2.near.net!news.mathworks.com!news.alpha.net!mvb.saic.com!news.cerf.net!pagesat.net!internet.spss.com!markrose
From: markrose@spss.com (Mark Rosenfelder)
Subject: Re: Dennett vs filling in (was Re: When is a simulation of a Y a Y? (Was Bag the Turing
Message-ID: <D3LsBB.2v0@spss.com>
Sender: news@spss.com
Organization: SPSS Inc
References: <D2xL96.AMB@spss.com> <D2z6t6.5r4@cogsci.ed.ac.uk> <D3AB9n.Bs3@spss.com> <D3Fxt2.L2L@cogsci.ed.ac.uk>
Date: Tue, 7 Feb 1995 00:06:46 GMT
Lines: 126

In article <D3Fxt2.L2L@cogsci.ed.ac.uk>,
Jeff Dalton <jeff@aiai.ed.ac.uk> wrote:
>markrose@spss.com (Mark Rosenfelder) writes:
>>Here and in other parts of this section (e.g. the only other section that
>>mentions blind spots, p. 8), Hardin uses entirely unobjectionable, neutral
>>language, saying only that we are not aware of the blind spot (or of our
>>own saccades, or of the shadows of retinal blood vessels, etc.).  
>>
>>However, this passage seems to me to go much further than merely "saying
>>...that we don't notice the blind spots", as you claim; it actually declares 
>>that the blind spot is filled in "from adjoining retinal regions", and even
>>comments on how remarkable this process is.  Hardin does not say where
>>this notion comes from; one would have to examine his own sources to find
>>out.  I don't think that Dennett is misinterpreting anything Hardin
>>says about "filling in".  
>
>The part about "from adjoining retinal regions" seems to me the most
>telling.  Thanks for pointing it out.  But Dennett omits it, so presumably
>he thinks it isn't needed as supporting evidence.

You know exactly what Dennett is thinking, based on what he doesn't say?
Isn't this just what you objected to in his discussion of Hardin?

>I would still say that what this "filling in" is more a place-holder
>than a theory about what's actually going on, and that includes
>filling in "from immediately adjoining retinal regions".  Hardin
>doesn't say enough in the paragraph above for us to tell what his
>views are in any detail.

If you mean that Hardin doesn't explain his views in detail, I agree;
but I don't agree that the ideas from the passage I quoted are a "place-
holder".  I don't think you're doing Hardin any favors here; what exactly do 
you think Hardin is calling "remarkable", if it's not a process of filling in 
in the brain?  

>>>Before Dennett made a big issue of "filling-in",
>>>why would anyone have thought it was a particularly questionable
>>>thing to say?
>>
>>This question, to my mind, quite misses the point.  It's like asking
>>why anyone would have thought that "simultaneous" was a particularly
>>tricky concept before Einstein made a big deal of it.
>
>I don't think there *is* anything especially tricky about "filling-in"
>as it seems to be used.  By likening it do "simultaneous", you're
>supposing that Dennett is right.  

Not at all, any more than that discussions of simultaneity in 1905 had
to assume that Einstein was right.  Perhaps Dennett is wrong; another
post suggested that he might in fact be wrong about whether any "epistemic
agents" in the brain care about the blind spot's contents.  But once he's
given an alternative to "filling in", arguments for "filling in" need
to be *justified*, not *assumed*.  And whatever exactly Hardin was saying
about filling in (we may differ on how far he was committing himself), he 
certainly offered no support for it.

>Of course, there *is* now, post
>_Consciousness Explained_, a reason to avoid talk of filling-in,
>namely that Dennett, and people convinced by Dennett, will apply
>a distorting interpretation to what you say.

You haven't shown that Dennett is distorting anyone.

>>As for whether this idea is a relic of the Cartesian Theater-- what
>>would it take for you to accept that Dennett has "shown" this?  Citations
>>of Descartes, and discussions of the pineal gland?  All Dennett has to
>>show, IMHO, is that the authors he is discussing are assuming that the
>>brain has to construct a *visual image* out of what the eyes see, for
>>some part of the brain to look at.  Hardin's talk of filling in the blind
>>spot certainly sounds like such an assumption is at work, perhaps
>>unconsciously.
>
>Ah, unconsciously.  So no matter what even Hardin *says* in an attempt
>to clear his name, we might *know better*.  "Cartesian materialism,
>the view that nobody espouses but almost everybody tends to think
>in terms of" [Dennett] strikes again.

Talk about distortions.  What has Hardin said to "clear his name", and
where does Dennett reject those statements?  Whatever Dennett has done to
annoy you, is it really necessary to invent charges from thin air against him?

Pointing out an assumption that hasn't been explicitly stated or justified
is not an evil thing-- it's a service, a step forward.  It means that the
assumption can be critically examined, and either supported or rejected.

Perhaps you think that people are always very clear on what they are or
are not assuming about the world.  If so, I disagree.  Science very often
progresses by questioning assumptions we didn't even know we were making.
And even after a scientific revolution, it can take a very long time for
all the discredited assumptions to die out (if they ever do).

>I think it's fairly clear what Dennett means by the Cartesian Theater,
>and the pineal gland needn't be involved.  But he seems to take it for
>granted that there's a Cartesian influence and doesn't spend much
>(if any) time arguing that there is or explaining how it works.
>(Does he ever say it's a meme?)  He sometimes refers to the Cartesian
>Theater as the "traditional view".  That, plus talk of vestiges or
>(from your earlier article) relics, tends to suggest that it's
>something we've picked up (in attenuated form) from the past.  

Again, you haven't said what it would take to "show" you that these views
are relics of the Cartesian Theater.  So far as I can see, whatever I or
Dennett say, you can respond "But that didn't convince me."  

I think you're taking Dennett's rhetoric much too literally.  "The Cartesian 
Theater" is just a convenient label; he refers to Descartes at all simply as 
a rigorous and influential expositor of rational dualism; he doesn't claim 
that the assumptions he is criticizing actually derive directly from Descartes.

My reading of what he's doing is to point out assumptions that all of us,
including himself, started out with, and to subject them to critical
examination.  He of course ends up rejecting them.  After reading him,
you may or may not agree; but if you don't agree you will have to come up
with reasons for what may have previously been unexamined presuppositions.

His claim is not at all that Hardin et al. are dualists, or believe in
figment, but that they've said things that seem to assume, without 
justification, that the brain constructs a visual image out of what the eyes 
see, for some other part of the brain to look at.  In the case of Hardin,
as I've said, the case seems to be justified: Hardin's statements about
filling in from adjoining retinal areas are not explicitly supported.
You seem to be worried that Hardin, if he read these passages in Dennett,
would cry out, "I've been misinterpreted!"  That's possible; but he might
equally decide to supply more backing for his statement, or modify his
statements to make no theoretical presuppositions.   Frankly I find these
possibilities more complimentary to Hardin.
