On 27 Apr 2017, at 23:22, Brent Meeker wrote:
On 4/27/2017 1:43 AM, Bruno Marchal wrote:
On 26 Apr 2017, at 22:38, Brent Meeker wrote:
On 4/26/2017 7:28 AM, Bruno Marchal wrote:
On 26 Apr 2017, at 00:19, Brent Meeker wrote:
On 4/25/2017 1:59 AM, Bruno Marchal wrote:
On 25 Apr 2017, at 01:13, Bruce Kellett wrote:
On 24/04/2017 6:07 pm, Telmo Menezes wrote:
On Mon, Apr 24, 2017 at 6:08 AM, Russell Standish <[email protected]
> wrote:
On Sun, Apr 23, 2017 at 11:49:51AM +0200, Telmo Menezes wrote:
Ok, so you are rejecting computationalism. Computationalism
is the
hypothesis that our mind supervenes on computations (sorry
Bruno, it's
easier to write for the purpose of this discussion :). You
are
declaring that mind supervene on the physical brain.
That is not it at all. We've clarified with Bruno many times
that
computational supervenience is compatible with physical
supervenience. Which is just as well, as otherwise it would
be so much
the worse for computationalism.
I have no doubt that the brain is a physical computer, and that
computations performed by the brain are no different from any
other
computations.
We are discussing physicalism and computationalism, and if
they are
compatible or not, correct?
Bruce repeatedly makes variation of the claim: "look, the
brain is
physical and the brain generates consciousness, these are the
facts".
This is what I am replying to. It's an argument from
authority that
leaves no space for debate or reasoning.
First, it is not an argument from authority, it is an argument
made on the basis of all the available evidence --
consciousness supervenes on the physical brain.
Second. An argument from authority is not necessarily a reason
to reject that argument. Because life is short and we cannot
be experts in absolutely everything, we frequently have to
rely on authorities -- people who are recognized experts in
the relevant field. I am confident that when I drive across
this bridge it will not collapse under the weight of my car
because I trust the expertise of the engineers who designed
and constructed the bridge. In other words, I rely on the
relevant authorities for my conclusion that this bridge is
safe. An argument from authority is unsound only if the quoted
authorities are themselves not reliable -- they are not
experts in the relevant field, and/or their supposed
qualifications are bogus. There are many examples of this --
like relying on President Trump's assessment of anthropogenic
global warming, etc, etc.
Third, since it is now clear that the term "physicalism"
refers to the belief in primary matter, I have never ascribed
to "physicalism".
Usually I use "Weak materialism" for the "assumption/belief" in
primary matter. primary means "in need to be assumed";
Something is "primary" if to get its existence we need to
assume it, or something equivalent. For example, we know since
the failure of logicism that numbers are primary. We cannot
derive them from logic.
But we can - and did - derive them from observation and
manipulation of objects. Numbers came from measuring the size
of sheepherds, the steps from one place to another,... You
learned them that way at your mother's knee.
I was using "derivation" in the logical or mathematical sense.
Size of sheepherds can be used for illustration, but if you think
we can derive numbers from sheep, show me a theory of sheepherds
not using numbers, and then a logical derivation of number
existence from that.
Haven't you read Gamow's "One, Two, Three, Infinity".
Yes. Lovely book, but slightly responsible for my early belief in
wave reduction ...
The point is that to derive numbers from sheepherds in the logical
way,
?? You frequently point out that logicism failed. Then you turn
around and demand that numbers be "derived in a logical way"!?
From the sheepherd, in the theory according to which sheepherd is
considered primary. My answer was in a context.
you would need to define sheep in first order logic, and this as
primitive (not using numbers, nor sets, etc.). That is simply
ridiculous. I cannot even conceive one axiom apt to that task.
The world (an sheep) are not axiomatic.
Indeed. They are thought semantically, like "arithmetic" as opposed to
PA or RA, or ZF, etc.
That's why you have to refer to dreams in your theory.
Yes. A dream is a computation seen by those supported by the
computations, which used the first person []p & p, and the "& p" is
semantical (that is why []p & p cannot be defined with any symbols).
It is a bit like the difference between we derive atoms from the
observation all around us, and we explain the origin of atoms
from the consumption of star.
What you said is correct, but not relevant in the search of a
fundamental theory.
You only think so because you assume that arithmetic and logic are
fundamental.
You need some amount of that idea to even define computationalism,
or just Church-Turing thesis, universal number, etc. Physicist
assumes this too.
Physicists don't assume, they test and use what works.
Of course physicists assume. They lack innate clairvoyance.
Of course, we can derive them from the combinators theory, but
combinators are Turing equivalent to the numbers.
Weak materialism is just the belief in some matter, and that
matter cannot be explained by something non material.
I must used "weak" before materialist, because the term
"materialist" has a special meaning in philosophy of mind: it
means that only matter "really" exist, ad is opposed to dualism
(matter and mind exists) and immaterialism monism (only
immaterial objects exist)
Physicalism is the assumption, in metaphysics/theology, that
physics is the fundamental science to which all other sciences
can be, in principle, reduced.
We can conceive some forms of physicalism which are
immaterialist, for example Tegmark is close to this. But
usually, most physicalist are weak materialist, and often I use
weak materialism and physicalism as being quasi the same thing.
I am an empirist, indeed, I extracted "computationalism" from
biology, well before I knew about Church and Turing. And I take
physics very seriously, and as the ultimate judge. Indeed, my
point is that if mechanism is correct, the physical reality is
"in the machine's head", and that is what makes mechanism
testable: by comparing the physics in the head of the machine
with the physics inferred from the observation.
Testable requires not comparison, but falsifiability. So if
computationalism predicts things that are not observed, as it
must if it is to explain thoughts, then it seems it if
falsified. It is saved only by the too cheap trick of saying
everything exists.
Not everything, just 0 and the successors.
Then we get all computations as a theorem, and all the rest as
computation
No, you also require addition, multiplication, induction, rules of
inference and the UD and the realism of arithmetic.
Arithmetical realism is enough, except for the modus ponens rule.
Induction is not assumed.
"Getting a theorem" is only showing there is a truth preserving
inference chain from some axioms.
yes. And RA proves the existence of the computations.
seen from the first person self-referential pov of the machines
emulated by those computation.
But those "persons" are characterized entirely by "beliefs" about
arithmetic.
Why. The theorem saying that ZF proves infinity is also a theorem
of arithmetic. Likewize, the theorem saying that Brent sent me this
mail and believes this or that, belongs also to elementary
arithmetic (although the proof might be long and deep).
The trouble is that also there is a theorem in elementary arithmetic
that Brent did not send me this email.
In a different universe, apparently. Same with QM-without-collapse.
That is why consciousness differentiates all the time.
Most arithmetical creature believes in much more than arithmetic.
And also much less.
Yes, but less. Anyway, that was for getting a conclusion, and it is
unclear what you try to explain here.
We judge theories by how well they predict the world we observe.
Then physics fails up to now, and at least we know why, because we
know that if the physical reality is primary, we need a non
computationalist theory of mind, but are not even close to have
anything like that.
Physics predicts that the effect of tequila, but not lemonade, on my
brain will muddle my thoughts, my memory, and perhaps temporarily
elminate them. Can computationalism predict this?
Computationalism predicts that if things continue to work, physics
makes sense, and we get the tequila qualia taste as a surprise gift,
where the honest materialist must eliminate the person if he want to
keep mechanism.
We do have a non-computationalist theory of mind, or at least the
same kind of hope-for-a-theory as the computationalist theory. It
is the one JC enunciates, i.e. that certain information processing,
specifically that which underlies intelligent, reflective behavior,
entails consciousness.
OK then. If it is non computationalist, it might work. But just saying
"non-computationalist information processing" is hardly a theory. Just
an hope.
I like your theory as a research project - maybe it can predict
something we don't already know. But I balk at accepting some of
the things you say you've proven.
I have proven that there is a measure problem if we assume we can
survive with a digital physical brain. It is a problem. Some could use
this against computationalism, but then I show that incompleteness
temper that enthusiasm against comp by deriving an intuitionist logic
for the first person pov, and a quantum logic for the observable.
That's all. It is the necessity to open again the old immaterialist
position in theology, like Plotinus, etc.
In outline, you say your argument is a reductio. You assume that a
human brain can be replaced by something else that does the same
computations.
... that there is a level where we can do that. yes.
Then you invoke arithmetical realism and Church-Turing to say that
computation is not physical,
Computation is a notion born non physical. You need as much
arithmetical realism and Church thesis to believe in physical
computation. And you need arithmetical realism, Church-Turing thesis +
an act of faith in Aristotle "second God" to believe in primarily
physical computations.
yet it is derivative or inferred from our experience
Not at all. I can explain again, but the notion of computation is born
in the foundation of math, and only the human intuition of the "number
part" might be said influenced by nature, but all scientist assumes
the number. None derive them (or Turing equivalent) from anything more
primitive.
One of the first definition of computation, the SK combinators, was
coming from the goal to eliminate the variables in logic (abstract
goal, no observation here), and the discovery of QM shows that both S
and K do not even exist in nature (S duplicates information, and K
eliminates information, so cannot be unitary).
which is a computation. The absurdity, if I've understood this, is
that idea of physical substitution leads to a conclusion that
nothing physical is needed.
The absurdity is that the first person experience in physics has to be
a sum on all computations (to be short). So even if a physical
universe exists, it *cannot* have any influence on my prediction.
Physics lose *all* its prediction power. Computationalism saves
physics, we should say, but makes it more modest when wandering on
metaphysics.
Further, you conclude that this absurdity implies that primary
physics is otiose. I see two problems with this.
First, the absurdity just comes from the assumption of arithmetical
realism - so that computation need not be instantiated physically.
?
That assumption is not something entailed by "Yes, doctor".
?
Keep in mind that arithmetical realism is only the believe in the
standard notion of numbers. It is assumed by all mathematicians and
physicists. I make it explicit because I put all the assumptions on
the table. Without it, we cannot even define what a digital machine
is, nor a brain, nor a doctor. Only Physical ultrafinitists have a
problem with arithmetical realism, but there are an ultra-minority.
For them, computers do not exist at all, and they will never say "yes"
to a doctor.
Second, when one uses a reductio, after reaching an absurdity to you
go back and reject some premise. But this case you reject "primary
physics"...which was not a premise. I "go back" and reject
arithmetical realism...which was a premise.
No problem. That was the point (of the UDA+MGA). It shows only that
(~materialism v ~mechanism).
But then, as I said, it is easier to explain the illusion of matter to
a relative digital machine/number in arithmetic, than to explain the
illusion of consciousness (if that makes sense) to a piece of primary
matter that nobody has ever seen. By rejecting arithmetical realism
(believed by everybody) just to invoke a god (Primary Matter), you
seem a bit like a creationist who says that the theory of evolution is
nice and explains a lot of things, but fails and must be abandoned
because it obviously miss how God could have done all that in 6 days.
But no problem, UDA just shows (~materialism v ~mechanism), except
that it indicates already that if we keep mechanism, matter has to be
explained by a measure on all computations, modalized through machine
self-reference.
You should not see computationalism as a competitor with physics, but
on the contrary, as the savior of physics in the mechanist frame, and
if that does not work, we have to abandon computationalism (or to bet
on a malevolent "Bostromian emulation/dream").
Bruno
Brent
bruno
I don't see any persons like that.
Brent
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