One argument that he deconstructs is the "cells are replaced so we're not even the same body" argument. Surprisingly, he doesn't mention that brain cells have traditionally been held NOT to do so, though this may have been an abandoned argument in light of recent studies that suggest some regrowth\repair may be possible.

Cells are indeed replaced quite quickly at the periphery of our body, like the limbs, the stomach/intestine (remember that they technically face the exterior!!), but cells in mission critical organs like the brain and the heart are not repaired when they die, most of the time. Yes, in the brain cells are replaced and pathways are rewired, although with inevitable change, but the heart remains mostly the same, always beating. Thus even a minor heart problem can be crippling and irreversible. That's also why bypass surgery is sometimes the only solution when an artery attached to the heart becomes clogged (a recent study showed 40% regeneration of heart tissue over 70 years, while we thought 0% some years ago).

It's also been suggested that consciousness is all post-hoc. That everything we experience has already happened, even if it's fractions of the second later. That we "feel" like we've made decisions but really we're just experiencing the machinations of the brain's processes after the fact. This works pretty well for dualism, because then you no longer have to account for influence on the process. (However, it blows a hole through the theories of most dualists, who are arguing for a soul and the free will that accompanies it.)

If we look closely, we can see it cannot be otherwise. What you call "consciousness" here is really "conscious awareness", the intertwining of consciousness and awareness. Consciousness is intentional, though not really causal, and awareness is plainly passive. Consciousness is really like a recursive loop program, which has a variable (the object that is aimed at) which can refer to any kind of object in the world, be it the mental world or the perceptual, outside world. Consciousness cannot then be said to be responsible of the actions that follow it aiming at an object, nor can it be said strictly to be choosing what to aim at, but what we know is that this is where our illusion of freedom comes from: the selecting of objects to be aimed at intentionally. No doubt part of it is unconscious, like when you turn your head after seeing something move on your peripheral vision, but since consciousness is recursive, it must be able to change the reference of its own variable. That does not mean it has absolute freedom in choosing the new reference, in fact it can't be since we're not omnipotent, but it must have a means to do so, otherwise the very existence of self-awareness would be useless. If consciousness was strictly determined by the "outside" i.e. by external processes from elsewhere in the brain, then consciousness + awareness would not give rise to the kind of self-awareness that is evident in higher mammals. As we know, evolution does not do things for no reason, i.e. it must have a purpose, which gives an adaptation benefit. Here the adaptation benefit could be that by doing this we can reflect on some of our own thought processes and can influence their course (by "concentrating" on them, making them the aim of our intentional consciousness). It may also be that we can broaden our intentional objects to things which are not in our immediate senses/memory, i.e. imagination.

You are right though that dualism is not that easily dismissed, but it is always in the end shown to be either naïve, unfounded or plainly superfluous (i.e. useless per Ockham's razor).

>> ^HadouKen24:
In the current (read: last fifteen years or so) state of the discussion of the philosophy of mind, the argument for or against dualism does not hinge upon whether science has yet provided a coherent account of consciousness--we all know it hasn't--but whether it can in principle provide such an account. It is not obvious that any advance in science could provide us with a satisfactory account of consciousness. It is thus not an argument from ignorance.

One could have said the same on the theory of evolution before we found out about DNA. Before the discovery of DNA one couldn't possible concede of a satisfactory way to fully describe the origin of the species because there didn't exist a way to explain the way information could passed on through generations and how that information changed minutely to make the "survival of the fittest" possible.

>> ^Almanildo:

Postulating a new kind of physical interaction isn't substance dualism; you have to take the new stuff completely out of physics to call it dualist.


Well, you have to take it completely outside of physics to call it substance dualism. Under property and predicate dualism, it is be difficult or impossible to give a thorough account of the mind without speaking of the underlying physical processes which create or are associated with it.

>> ^Almanildo:
^HadouKen24
That doesn't address my main point, which is that determinism isn't really relevant.


Generally not, but under something like Penrose's conception of the mind, it would be. The arguments that quantum indeterminacy is insufficient for free will break down if the mind is fundamentally a quantum phenomenon.

>> ^Almanildo:
I guess I misunderstood your point. I thought that your statement that "we can't presently percieve" something meant that we might be able to percieve it in the future. But then I don't see your point about how today's non-physical is tomorrow's physical. If we can percieve it, it's physical. If we in principle can't percieve it, I argue that it's irrelevant, because it can't affect our bodies.
I need to make sure I know the direction the argument is coming from, because I'm not sure I'm reading the same message you intended to convey.



There are many things we know to exist that we technically can't perceive. Everything out of range of our sensory organs has to be modulated into an in-range format to be perceivable. Some of these things were only discovered once the means of modulation were invented, and others were postulated to exist before eventually being proven.
Tiny living creatures crawling under my fingernails? Absurd!
Beams of "invisible light" that can pass through my body? Preposterous!

In terms of "today's non-physical is tomorrow's physical", I believe what he means is that the current physical model is incomplete. Eventually, the model will be more complete. Everything that's in the revised model that wasn't in the old model represents that progression.

To answer a question you'd asked earlier, a couple of times - understanding that there's something present (and arguably perceivable) that isn't accounted for by the current physical model serves the purpose of reminding us that we're not done yet. Reminding us that there's a significant gap between what we already "know" and what we know is left to learn. That we cannot be content with the model we've got because it's missing some seemingly very critical parts.

>> ^Lodurr:
I don't see the point to that definition of substance dualism. How much farther removed from "physical" can you get than existing in a separate, invisible dimension? All the statements substance dualism makes about consciousness can still be true in a scenario where consciousness is part of an extra-physical dimension.
I watched Dennett's talk, the salient point comes at the conclusion which is "free will exists in the sense that matters," which is to say "real" free will doesn't exist, and that the universe is still ultimately deterministic in his view.

I guess I misunderstood your point. I thought that your statement that "we can't presently percieve" something meant that we might be able to percieve it in the future. But then I don't see your point about how today's non-physical is tomorrow's physical. If we can percieve it, it's physical. If we in principle can't percieve it, I argue that it's irrelevant, because it can't affect our bodies.


You're basically right about Dennett. Consider, though, that so-called "real" free will would be indistinguishible from Dennett's kind of free will, since you can never reproduce an event exactly.

>> ^Almanildo:

Postulating a new kind of physical interaction isn't substance dualism; you have to take the new stuff completely out of physics to call it dualist.

On the subject of determinism, we don't really know whether physics is deterministic. My belief is that it's not. However, it's not a given that determinism is even relevant for the problem of free will. Daniel Dennett argues (quite convincingly in my book) that it's not.


I don't see the point to that definition of substance dualism. How much farther removed from "physical" can you get than existing in a separate, invisible dimension? All the statements substance dualism makes about consciousness can still be true in a scenario where consciousness is part of an extra-physical dimension.

I watched Dennett's talk, the salient point comes at the conclusion which is "free will exists in the sense that matters," which is to say "real" free will doesn't exist, and that the universe is still ultimately deterministic in his view.

I think it's fairly obvious that quantum indeterminacy is generally incapable of showing that we have something like free will. There are arguments which may show that, under certain conditions, quantum indeterminacy is quite capable of generating something more or less like free will. Roger Penrose (the brilliant mathematician, physicist, and philosopher who co-formulated the Penrose-Hawking theorems) advanced such an argument, attempting in Shadows of the Mind to show quantum effects in microtubules of the brain are responsible for both consciousness and free will. However, further research into the physics of the brain showed this line of reasoning to be ultimately defunct.

>> ^Almanildo:
>>
However, it's not a given that determinism is even relevant for the problem of free will. Daniel Dennett argues (quite convincingly in my book) that it's not.

>> ^Lodurr:

That's the point, that today's "non-physical" is tomorrow's "physical." Dualists argue that consciousness results from physical interactions that we can't presently perceive, and that these interactions aren't limited to our perceivable dimensions.
@Almanildo, the problem with classical physics-based consciousness is that physics is deterministic, and our experience of consciousness is non-deterministic. We've recently gone from thinking that we were completely free-willed to a more complex understanding of brain chemistry and motor functions, but the basic experience of awareness and self-guided thought seem fundamentally impossible to pin as deterministic.

Postulating a new kind of physical interaction isn't substance dualism; you have to take the new stuff completely out of physics to call it dualist.


On the subject of determinism, we don't really know whether physics is deterministic. My belief is that it's not. However, it's not a given that determinism is even relevant for the problem of free will. Daniel Dennett argues (quite convincingly in my book) that it's not.

In the current (read: last fifteen years or so) state of the discussion of the philosophy of mind, the argument for or against dualism does not hinge upon whether science has yet provided a coherent account of consciousness--we all know it hasn't--but whether it can in principle provide such an account. It is not obvious that any advance in science could provide us with a satisfactory account of consciousness. It is thus not an argument from ignorance.

Granted, there are few substance dualists around in philosophy anymore--most dualists are property or predicate dualists. Nonetheless, the claim that dualism is simply an argument from ignorance applies equally to both.

>> ^Psychologic:
The substance dualism argument is an "argument from ignorance". It rightfully points out that current theories of perception are not complete, but then begins filling in those gaps with unsupported speculation. The fact that our theories are not complete is not evidence for the existence of souls any more than a person's inability to identify a light in the sky is evidence of alien visitation.

>> ^ReverendTed:
>> ^gwiz665:
but one thing is fairly evident, there is no ethereal element to it.
How is this "evident"? The physical model does not accommodate unified experience. Just as you suggested, the body and the brain are simply organic machines. They should only "do" - impulse in, algorithm run, impulse out, and there is no reason for them to "be aware" of it. There is no step in the prescribed process where a cell does anything more than pass along an electrical stimulus to some other cells. (Which, again, I'm fine with - it's just that awareness remains completely unaccounted for.)


It is evident, because we cannot observe it directly OR indirectly. You'll agree with me, I presume, that we cannot observe something that is not material or physical, yes? Much like we cannot observe dark matter/energy (if that exists), but we can see the influence it has on the physical world.

We cannot see any influence on the physical brain from the consciousness, it goes the other way around . the physical brain determines the conscious thought.

And the consciousness is not aware of how the input/output works either, like I said, we have no introspective knowledge other than what the brain presents to "us". A car's speedometer does not know how much CO² the car releases into the world either. (Obviously there are some differences between a static closed thing like a speedometer and a dynamic, changing system like a brain, but it's a metaphor. )

There is no step in a computer either, which would account for how we can perceive programs on it - we just can, because we use certain filters and tables, which determines what that particular 1 or 0 means. You cannot see whether you run word, firefox or world of warcraft on a computer very easily, by looking at the electrical impulses, but that's the only way we have to analyze the brain right now.

Imagine having to reverse engineer a program on a computer, with only the hardware available? It's possible, but fuuck, it's hard. That's what neuroscience is trying to do (I think).

>> ^Psychologic:

The argument for/against souls is irrelevant to philosophical dualism. Regarding the cause of consciousness, dualism is simply saying "Your princess is in another castle."

>> ^brain:
If elementary particles undergoing quantum effects isn't physical, then I don't know what is.


That's the point, that today's "non-physical" is tomorrow's "physical." Dualists argue that consciousness results from physical interactions that we can't presently perceive, and that these interactions aren't limited to our perceivable dimensions.

@Almanildo, the problem with classical physics-based consciousness is that physics is deterministic, and our experience of consciousness is non-deterministic. We've recently gone from thinking that we were completely free-willed to a more complex understanding of brain chemistry and motor functions, but the basic experience of awareness and self-guided thought seem fundamentally impossible to pin as deterministic.

IBM (among others) is making some nice progress simulating brain function with the intent of reverse-engineering the processes of cognition. Perhaps that will shed some light on these questions.

The substance dualism argument is an "argument from ignorance". It rightfully points out that current theories of perception are not complete, but then begins filling in those gaps with unsupported speculation. The fact that our theories are not complete is not evidence for the existence of souls any more than a person's inability to identify a light in the sky is evidence of alien visitation.

Anything that affects the physical world is testable, even if we do not currently have the tools to see it. If there are immortal souls then we will find the exact way in which they affect the physical world.

However, there are always people who begin with a conclusion and then look for evidence that supports it, and for such people any hole in our established understanding is evidence for their belief. Those are they types of people QS's video seems to address. There may be souls or whatever people think are there beyond death, but until we have actual evidence supporting that position then any confidence in such speculation is misplaced.

>> ^ReverendTed:
The problem with his argument is that consciousness (or at least awareness) IS non-physical, at least given our existing model.

This is an extraordinary claim with no evidence to back it up. Not knowing something simply means not knowing something. You can't say that since we don't know precisely how consciousness arises, we know it is non-physical. Indeed I don't know how it could possibly be non-physical, certainly you'll never find evidence for such a claim since nothing non-physical can be observed as it can never interact with anything that is physical. As for the idea of awareness as an external observer drawing from the brain's functions, I don't see what such a model adds to our understanding of the world. Such awareness can have no influence on the world, as you yourself pointed out, and this means it is entirely unnecessary to introduce such fantasies in order to explain the world.