Archive | Qualia RSS for this section

Should a materialist be an eliminativist?

In a previous post (which newcomers should read), I went into the problem of subjective awareness (or consciousness).

Bild

Like the great philosopher Thomas Nagel, I considered what a bat subjectively feels when it is sending out ultrasounds.
Try to imagine this for a few minutes.
I suppose that the large majority of my readers will acknowledge the fact they don’t have a clue what it feels like to be a bat in that particular situation.
But why is it the case, if this subjective feeling is nothing more than a complex physical phenomenon?

Nagel’s thought experiment consists in imagining a scientist of the future knowing absolutely all chemical and physical processes taking place in brain of the animal as it is emitting the ultrasound.

Would he know what the creature is experiencing?

Most people think intuitively it is obvious that a knowledge about the movements of the electrons in the brain would NOT bring him a knowledge about the subjective perceptions of the living thing.

But why is it so?

In the post I linked to I explain why this cannot lie in the fact that our brains are too different. To (modestly) quote myself:

“I’ve never understood how one can make sense of that in a materialist framework.
If the subjective experience is as material as the atoms of the chair I’m sitting on and the electrical processes of the computer I’m using, then why would a complete knowledge of physics allows me to know everything about both objects but not about the feelings of the animal?

Let us suppose that species A and species B dispose of brains enabling them to perfectly understand physics and chemistry while being radically different in other respects. It makes only sense to say that species A cannot know what species B feels if these very feelings are something MORE than physics and chemistry, that is if one form of dualism is true.”

Now materialists have answered me that no human scientist knowing everything could figure out what the bat feels because the human brain is not capable of processing such an amount of complex information.
Other materialists were more optimistic but seemed to recognize that there will always be a gap owing to the extreme complexity of the phenomenon and our own mental limitation.

At face value, such a response has a certain degree of plausibility

It is entirely true that the brain of living things are the most complex structure in the whole universe, far more complicated than a cluster of black holes taking over stars could ever be.

Bild

But there is a huge problem here. How on earth can a stupid bat be perfectly aware of its subjective experience, if it is something that our most brilliant scientists cannot (yet?) figure out?

I think that the following argument can be considered,

1) If the subjective experience of a bat is identical to a ensemble of brain processes, it is going to be extremely complex.

2) Our scientists could only be (partially) aware of this very complex processes if they disposed of much more knowledge than they currently do.

3) School children or anyone lacking the education, competence and physical knowledge cannot be aware of the experience.

4) A bat lacks all these attributes.

5) Yet a bat is perfectly aware of what it is feeling as it is sending out the ultrasound.

6) Thus this subjective experience cannot be identical to extremely complex physical processes.

6) logically follows from all the steps.

How can a materialist react to this?

1) and 2) are the excuses they came up with for explaining away our utter lack of knowledge of the bat’s experience as it emits the ultrasound.

3) logically follows from  1) and 2).

4) is obviously true.

Therefore I think it is fair to say that materialists will have to deny 5): the bat is not perfectly aware of its subjective experience.

But given the definition of subjective consciousness, this amounts to asserting that the bat is not perfectly aware of what it is aware of. Therefore this would mean embracing eliminative materialism, which is the belief that there is no such thing as phenomenal consciousness.

There is no such thing as being a bat or a bee. Or, to use the phrase of the great materialist neurophilosopher Thomas Metzinger, we should accept “being nobody”.

(I’ve used “conscious” and “aware” as synonyms in the entire post).

Some people will certainly quibble with my use of the word “perfectly”. I think it is justified in this context, given the nature of our experienced feelings.
If I am in pain, I know perfectly well what I am experiencing, feeling or sensing.
If there are bodily processes I am not aware of, they don’t belong (by their very nature) to my subjective conscious experience.

Nevertheless, I think that if you replaced 5) by “Yet a bat knows much better what it is feeling as it is sending out the ultrasound than what our best current scientists can figure out”,  the argument and its conclusion would remain largely unchanged.

I have used the example of a bat, but any extraterrestrial creature being radically different from us in the some way would do the job too.

I have just realized that my argument could be stronger if one were to consider a self-conscious bat-like creature possessing the intelligence of a seven-years old average human (and presumably living on another planet).

Although it won’t probably convince everyone, I think that what I have outlined here is a decent philosophical argument.

Addition: saying that the conscious experience of the bat is a representation produced by its brain does not seem to solve the problem since a representation itself is an ensemble of extremely complex physical processes (according to materialists).

On the feeling of a lonesome bat / Von den Gefühlen einer einsamen Fledermaus / Des sentiments d’une chauve-souris solitaire

To my mind, the existence of consciousness, of a subjective experience is one of the greatest mysteries of the entire universe.

I remember very well my feelings as I followed a course about the origin of life as a high-school student. I was a young atheist and I had no problem to believe there were (and still are) various plausible theories explaining how self-replicating systems can come into being.

Yet, I was deeply puzzled by the very existence of conscious experiences, which I associated at that time with every living things including bacteria.

So I was wondering: “how can a bunch of chemicals lacking any kind of subjectivity become a being with inner experiences and sensations?“

This was for me a startling but awe-inspiring unanswered and probably unanswerable question.

I believe that the intuitions I had then as a teenager are still largely valid, and that what has been called the “hard problem of consciousness“ is unanswerable within a reductive materialist framework.

I define Reductive Materialism (which I’ll refer to as RM) as the belief that everything which is real is identical with the sum of an ensemble of physical objects and processes involving the interaction of matter and energy.

It is certainly no problem for RM to state that the chair I’m sitting on is reducible to a heap of cellulose and lignite molecule occupying a certain shape in space.

But what about the following situation: a neuroscientist of the future has isolated a bat in a very complex machine which allows him to know exactly all chemical and electrical processes taking place within the brain of the poor animal. Suddenly, the bad emits an ultrasound and the researcher measures absolutely everything going on in its body.

Would he know what the bat subjectively felt as it sent out the ultrasound?

This is a question which the great philosopher Thomas Nagel famously raised in his groundbreaking article: „What is it lile to be a bat?“ which is freely available on the internet. I recommend readers unfamiliar with this line of arguments to first take a look at the groundwork.

The argument against RM one might derive from his ideas is as follows:

  1. if RM is true, someone knowing all the physical processes making up the subjective experience of a creature would know that experience

  2. a brilliant neuroscientist in such a position couldn’t know what the above bat experiences

  3. therefore RM is false

While examining the philosophical literature on this topic, I was astounded to see that most reductive materialists don’t contest the validity of 2). Intuitively, it seems to be obviously true.
Our current scientists are already capable of knowing a lot about the physics and chemistry of what’s going on in a bat’s brain, and I fail to see how any increase in our understanding of the synaptic impulses could provide us with a knowledge of the inner experience of our evolutionary distant fellow mammal.

This is probably the reason why it is premise 1) which is generally denied.
Many reductive materialists would say that even if we knew everything about the neurology of such a brain, we would not know what the being experiences because the structure of our own brain is too different.

I’ve never understood how one can make sense of that in a materialist framework.
If the subjective experience is as material as the atoms of the chair I’m sitting on and the electrical processes of the computer I’m using, then why would a complete knowledge of physics allows me to know everything about both objects but not about the feelings of the animal?

Let us suppose that species A and species B dispose of brains enabling them to perfectly understand physics and chemistry while being radically different in other respects. It makes only sense to say that species A cannot know what species B feels if these very feelings are something MORE than physics and chemistry, that is if one form of dualism is true.

So to my mind a reductive materialist has no other choice than to deny premise 2).
In spite of our strong intuitions an exhaustive knowledge of the brain’s physics of the animal would allow the scientist to know subjectively what the bat is experiencing.

But this seems very close to if not indistinguishable from eliminativism, the belief that what we refer to as our subjective experience is an illusion, probably spawned by evolution.

An obvious epistemological problem of this position is that the existence of our conscious experience is immediate and much more certain than complicated physical, chemical and biological theories.

In such a context, dualism (which I define as the belief that mental and physical processes are not identical) appears to be the most reasonable position.

 *******************************************

Meiner Meinung nach ist die Existenz des Bewustseins, einer subjektiven Erfahrung, ein der größten Geheimnisse des ganzen Universums.

Ich errinerre mich sehr gut an meine Gefühle, als ich als Gymnasiumschüler einen Unterricht über den Ursprung des Lebens hatte. Ich war ein junger Atheist und hatte kein Problem, zu glauben, dass es vielfältige plausible Theorien gab und immer noch gibt, die die Entstehung von selbstreplizierenden Systemen erklären.

Dennoch war ich über die Existenz von bewussten Erfahrungen sehr erstaunt, die ich zu dieser Zeit mit jedem lebendem Wesen (einschliesslich Bakterien) verband.

So fragte ich mich: “wie kann ein Haufen von Chemikalien ohne irgendwelche Art von Subjektivität ein Wesen mit inneren Erfahrungen und Empfindungen werden?”.

Dies war für mich eine verblüffende aber ehrfurchtgebietende unbeantwortete und wahrscheinlich unbeantwortbare Frage.

Ich glaube, dass meine Intuitionen als Teenager weitaus gültig sind, und dass was das “schwierige Problem des Bewustseins” benannt wurde in einem reduktiv materialistischem Rahmen unbehandelbar ist.

Ich definiere den reduktiven Materialismus (die ich fortan als RM bezeichnen werde) als den Glauben, dass alles was real ist mit der Summe eines Satzes von physikalischen Objekten und Prozessen identisch ist, die die Wechselwirkung von Materie und Energie involvieren.

Es ist ganz bestimmt kein Problem für RM auszusagen, dass der Stuhl, worauf ich sitze, reduzierbar auf ein Haufen von Zellulose- und Lignitmolekülen ist, die eine gewisse Form im Raum besetzten.

Aber wie sollte man die folgende Situation betrachten: ein Neurowissenschaftler der Zukunft hat eine Fledermaus in einer sehr komplexen Machine isoliert, die ihm erlaubt, genau alle chemischen und elektrischen Prozesse zu kennen, die innerhalb des Gehirns des armen Tieres stattfinden.

Plötzlich emittiert die Fledermaus einen Ultraschall und der Forscher misst wirklich alles, was in ihrem Körper vorgeht.

Würde er wissen, was die Fledermaus subjektiv fühlte, als sie den Ultraschall aussandt?

Dies ist eine Frage, die der große Philosoph Thomas Nagel in seinem bahnmbrechenden Artikel „What is it lile to be a bat?“ aufwarf, der auf Internet freilich verfügbar ist. Ich empfehle Lesern, die mit dieser Art von Argumenten nicht vertraut sind, zuerst einen Blick auf das Grundwerk zu werfen.

Das Argument gegen RM, das man aus seinen Ideen ableiten kann, sieht folgendermaßen aus:

  1. wenn RM wahr ist, würde jemand, der all die eine subjektive Erfahrung eines Geschöpfs ausmachenden physikalischen Prozesse kennt, diese Erfahrung kennen
  2. ein brillanter Wissenschaftler in einer solchen Position könnte die Erfahrung der Fledermaus nicht kennen
  3. deswegen ist RM falsch

Als ich die philosophische Literatur über dieses Thema untersuchte, war ich verblüfft, festzustellen, dass die meisten reduktiven Materialisten die Gültigkeit von 2) nicht bestreiten. Intuitiv scheint es, selstverständlich wahr zu sein.

Unsere gegenwärtige Wissenschaftler sind schon fähig, viel über die Physik und Chemie der Vorgänge in einem Fledermausgehirn zu wissen, und es gelingt mir nicht, einzusehen, wie irgendwelche Verbesserung unseres Verständnisses der synaptischen Impulsen uns die Kenntnis der inneren Erfahrung des evolutionär entfernten Säugetiers liefern würde.

Dies ist vermutlich der Grund, warum die Prämisse 1) generell verleugnet wird.

Viele reduktive Materialisten würden sagen, dass sogar alles über die Neurologie eines solchen Gehirns wissen würden, würden wir nicht wissen, was das Wesen erlebt, weil die Struktur unseres eigenen Gehirns zu anders ist.

Ich habe nie verstanden, wie das in einem materialistischen Rahmen Sinn machen kann.

Wenn die subjektive Erfahrung genauso material wie die Atome meines Stuhls und die elektrischen Prozesse meines Computers ist, warum würde dann eine vollständige Kenntnisse von Physik mir erlauben, alles über beide Objekte zu wissen, obwohl es für die Gefühle des Tiers nicht der Fall ist?


Lasst uns annehmen, dass die Art A und die Art B über Gehirne verfügen, die ihnen erlauben, vollkommen Physik und Chemie zu verstehen, obwohl sie in anderen Hinsichten extrem unterschiedlich sind. Es macht nur Sinn, zu sagen, dass die Art A nicht wissen kann, was die Art B fühlt, wenn diese Gefühle MEHR als Physik und Chemie sind, d.h. wenn eine Form von Dualismus wahr ist.

So meiner Meinung nach haben reduktive Materialisten keine andere Wahl, als Prämise 2) zu verleugnen.

Trotz unserer starken Intuitionen würde eine vollständige Kenntnis der Gehirnsphysik vom Tier dem Wissenschaftler erlauben, subjektiv zu wissen, was das Tier erlebt.

Aber dies scheint, dem Eliminativismus sehr nahe oder sogar damit identisch zu sein. Der Eliminativismus ist der Glaube, dass was wir als unsere subjektive Erfahrung bezeichnen eine Illusion ist, die vermutlich durch die Evolution hervorgerufen wird.

Ein offensichtliches Problem dieser Position ist, dass die Existenz unserer bewussten Erfahrung unmittelbar und viel gewisser als komplizierte physikalische, chemische und biologische Theorien ist.

In einem solchen Kontext scheint der Dualismus (den ich als den Glauben definiere, dass mentale und physikalische nicht identisch sind), die vernünfigste Position zu sein. 


Lothars Sohn – Lothar’s son

http://lotharlorraine.wordpress.com

Follow

Get every new post delivered to your Inbox.

Join 222 other followers