Let's walk through this slowly.

Harry notes that we can see that mind function depends on brain function. Take a chunk out of a brain, the mind associated with it doesn't work so well. Harry notes the insanity of thinking that taking away all the brain chunks leaves you with a working mind.

You object

This is a surprisingly common fallacy. Just because X depends on Y, it doesn't follow that X depends on nothing but Y. A phenomenon may involve more than just its most obvious failure point.

X = Mind. Y = Brain Chunks. Let X depend on Brain Chunks and Soul and Astral Flubber. If your mind is dependent on all of them for proper operation, then you can't speak when all your brain chunks are gone. End of story. You can play epiphenomenal games and argue that "yes, but you still have Soul and Astral Flubber." But who cares? All mind function is lost. I may "have" eternal and indestructible Astral Flubber, but what good does it do me?

Harry is clearly arguing against continued function after physical destruction, not against "having" a big pile of epiphenomenal astral hand bags, full of epiphenomenal astral stuff. He was hoping for functional minds after death, and noted how foolish that was.

No logical fallacy involved. Nothing to see here, move along.

I don't believe cars actually function via mechanical forces. It is the car's machine spirit which moves the vehicle.

If my car's timing belt gets broken or the alternator is malfunctioning, that doesn't stop the car. Clearly the machine spirit is strong enough to move the car even without a timing belt. However, the car's machine spirit will become angry and run sporadically, or lethargic at my poor maintenance and unwilling to start. The machine's spirit shall not be appeased until I take it to a proper mechanic so that he may assuage it with the holy rites and coax it to run again.

Those heretics who do not believe that cars have souls are simply making the Radio Fallacy. Fortunately I have seen the truth. Praise the Omnissiah!

(shrug) Sure. It's not a logical impossibility that all the valuable stuff resides in the soul, and that the brain serves only relatively valueless functions (akin to a radio), such that when we eliminate the brain the bulk of the value is preserved.

One question worth asking is how much attention I want to pay to "is X logically impossible?" vs "does there exist enough evidence for X to make it worth considering?"

Or, in the context you raise this in, "should we understand Harry to be talking about whether the soul hypothesis is logically possible, or talking about whether the soul hypothesis is worth considering?"

The utterance you quote is consistent with both readings.

It's not valid as a deductive argument, but it is Bayesian evidence in favour of naturalism. Also, the details of the observed effects of brain damage provide even more for naturalism rather than nonnaturalism.

you learned that the tooth fairy doesn't exist

Yes.

No, you learned that the tooth fairy doesn't exist

No.

Usually, the first thing to do when guessing about a random number from 1-100 is to split the possibilities in half by asking if it is more than 50 (or odd. Etc.)

The tooth fairy example gets a variety of responses, from people insisting it is just objectively wrong to say "the tooth fairy doesn't exist" to those saying it is just objectively wrong to say the tooth fairy was really my mother. I happen to agree with you about what the best way is to describe what went on in this specific case. However, this is a standard blegg-rube situation that is unusual only in that it is not clear which way is best to describe the phenomenon to others.

There is a constellation of phenomena that correlate to each other - the fairy being female, being magic, having diaphanous wings, collecting things for money, those things being stored under pillows, those things being teeth. None of these is qualitatively essential to be a tooth fairy to most people than "having ten fingers" is essential to being human. If tomorrow we learn that magic is real, a female sprite collects teeth from under pillows, and does so on the back of a termite (and has size-changing technology/magic, why not?), most people would naively say "the tooth fairy does not fly, but burrows on the back of a termite". That's OK, but not great if the true nature of the situation is not recognized, and they fall into error if they think "tooth fairy" has a meaning divorced from flight. Likewise, those who say "there was never a 'tooth fairy', there is rather the 'burrowing tooth fairy'" are right that there was never a thing exactly like the classic description, but this group makes an error if they demand the first stop calling the "burrowing tooth fairy" the "tooth fairy".

There is more to say, an individual who makes up explanations ad hoc is not communicating, and the relative confluence of idiolects is valid because of the tinkerbell effect. that makes saying "No, you learned that the tooth fairy doesn't exist" really peculiar, in the face of the many who hold the opposite position, likewise endorsed as language by common usage!

When it comes to "morality", the constellation of things represented with a token labeled "second order morality" had several stars, significantly organized around a few (mutually contradictory, but all validly denoted by the word "morality") sets of answers to these eight questions in the SEP on Moral Reasoning:

How do relevant considerations get taken up in moral reasoning? Is it essential to moral reasoning for the considerations it takes up to be crystallized into, or ranged under, principles? How do we sort out which moral considerations are most relevant? In what ways do motivational elements shape moral reasoning? What is the best way to model the kinds of conflicts among considerations that arise in moral reasoning? Does moral reasoning include learning from experience and changing one's mind? How can we reason, morally, with one another? What is the importance of institutional authority and social roles to the structure of moral reasoning?

One characteristic of things often (and validly) called "morality" is that they include the following among other pieces to answer the above questions: "'That which is good' is an ephemeral property that is infused in things in a dualistic way, it can be separate from all concerns beings may have, "good" can be binding in a way that is tautological and pointless...etc.

Reductionism continues the tradition of "morality", like other words, not meaning exactly what it did in the past, and it may be better to think of it as error theory in some cases. But all new theories claim the ones they supersede are in error, and there is nothing special about "morality minus magical deontology" or "moral reductionism" that one should consider them bad English by the usual standard.

After typing all of this, it strikes me that cars are a better example of no one component being essential. Cars without wheels will be "flying cars", unless they get sufficient lift and air etc. such that as one goes down the line of models from flying jalopy to sports flying car, each successive flying car will be called "car" by fewer and fewer people as it more resembles a fighter jet or so...as perhaps our descendants will call nuclear-powered flying vehicles.

The important thing is that reductionism gets it right when describing reality, the problems with deontology etc., and explains why people think erroneously, and it then proceeds to tell one how to act such that first order moral claims have meaning. If despite all that, you want to focus on its erosion of folk theories to call it an error theory, that is understandable, but it will be uninteresting if you say to the multitude "It is wrong(RC) to call reductionism 'moral'(RC)," since it is not wrong(everybody who recognizes not to misuse language by fixating on a connotation that often went along with a word when the contents described by that word are otherwise vindicated and under discussion, and we're discussing language which means 1) constelations and 2) tinkerbell).

I'm pointing out that what you claim to be the meaning of 'morality' isn't what people mean to be talking about when they engage in moral discourse.

When I was young, I learned that the tooth fairy was really my mother all along.

What do you think of that?

(This isn't meant to be insulting or anything similar.)

Ordinary moral debates aren't about the meaning of "ought".

I know that, which is why I said "Purported debates about the true meaning of 'ought'" rather than "ordinary debates, which are about the true meaning of 'ought'".

They're about the first-order question of which actions have the property of being what we ought to do. People disagree about which actions have this property.

Please be careful not to beg the question. People agree that there is such a property, but that is something about which they can be wrong.

They aren't stipulatively defining the meaning of 'ought', or else their claim that "You ought to follow the prescriptions of balancing equation Y" would be tautological...

Rather, they aren't trying to stipulatively define the meaning of 'ought', or else their claim that "You ought to follow the prescriptions of balancing equation Y" would be tautological.

In fact, due to people's poor self-insight, time limits, and the sometimes over-coarse granularity of language, they do not stipulate their actual balancing equation. Had they perfect insight and ability to represent their insights, it would be such a tautology. They would cease to speak like that had they the additional insight that for it to do the work it is called upon to do,"ought" is a word that needs grounding in the context of the real reasons for action of beings More generally, they are speaking an idiolect even regarding other definitions.

...rather than a substantive claim as it is obviously meant to be.

It's meant to be such a claim, but it is in error because the speaker is confused about morality, and in a sense is not even wrong. They are claiming some actions have an objective moral valuation binding upon all intelligent beings, but they may as well claim the action has the property of being a square circle - or better yet, a perfect circle for pi is exactly 3, which is something I have witnessed a religious person claim is true.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I don't understand either why you believe as you do or what good justification you might have for it.

I can see why one might want to make truth claims in which it falls out the folk have the least amount of confusion to be embarrassed about and are least wrong, and if one begins with the assumption that there are "moral facts" in the strongest sense, that's a good start. However, that neither prevents one from having to say they are wrong about an enormous amount nor does it prevent one from having to claim that others, such as me, are wrong about moral facts. I can also see how it might be comforting were moral facts real in that sense and how the world might be better off if people believe in them, but obviously those things would not make them true.

At least you seem to understand the position you are arguing against and I am advocating. You repeatedly have tried to dissuade me from it by pointing out extensions of my position and counting on me to disclaim it from reductio ad absurdum. But it always seems to be by appealing to the same notion, that people simply cannot be wrong about some sorts of things they believe, which is a position I reject.

So, assuming I bite the bullet and don't find it implausible that some people are fundamentally confused when they make moral claims, what other reasons might there be to agree with them? Why should I believe that intensionally defined "objective morality" has any extension at all?

But moral language doesn't plausibly function like this.

It's not plausible(RC, 7/1/2011 4:25 GMT), but it is plausible(LD, 7/1/2011 4:25 GMT).

Compare: "I am tall." "No, I am not tall!" Such an exchange would be absurd -- the people are clearly just talking past each other, since there is no common referent for 'I'.

It's not impossible for people to be confused in exactly such a way.

It's perfectly sensible for one person to say, "I ought to have an abortion", and another to disagree: "No, you ought not to have an abortion". (Even if both are logically omniscient.)

That's begging the question.

That intuition pump imagines intelligent people disagreeing, finds it plausible, notices that intelligent people disagreeing proves nothing, then replaces the label "intelligent" with "omniscient" (since that, if proven, would prove something) without showing the work that would make the replacement valid. If the work could be shown, the intuition pump wouldn't be very valuable, as one could just use the shown work for persuasion rather than the thought experiment with the disagreeing people. I strongly suspect that the reason the shown work is unavailable is because it does not exist.

Eliezer's reductive view on which the very meaning of 'morality' differs from person to person.

Forget morality for one second. Doesn't the meaning of the word "hat" differ from person to person?

It's perfectly sensible for one person to say, "I ought to have an abortion"

It's only sensible to say if/because context forestalls equivocation (or tries to, anyway). Retroactively removing the context by coming in the conversation with a different meaning of ought (even if the first meaning of "ought" was "objective values, as I think they are, as I think I want them to be, that are universally binding on all possible minds, and I would maintain under any coherent extrapolation of my values" where the first person is wrong about those facts and the second meaning of "ought" is the first person's extrapolated volition) introduces equivocation. It's really analogous to saying "No, I am not tall".

Where the first person says "X would make me happy, I want to feel like doing X, and others will be better off according to balancing equation Y if I do X, and the word "ought" encompasses when those things coincide according to objective English, so I ought to do X", and the second person says "X would make you happy, you want to feel like doing X, and others will not be better off according to balancing equation Z if you do X, and the word "ought" encompasses when those things coincide according to objective English, so you ought not do X", they are talking past each other. Purported debates about the true meaning of "ought" reveal that everyone has their own balancing equation, and the average person thinks all others are morally obliged by objective morality to follow his or her equation. In truth, the terms "make happy" and want to feel like doing" are rolled up into the balancing equation, but in it (for Westerners) terms for self and others seem as if they are of different kind.

What is objection (1) saying? That asserting there are moral facts is incompatible with the fact that people disagree about what they are? Specifically, when people agree that there is such a thing as a reason that applies to both of them, they disagree about how the reason is caused by reality?

Do we not then say they are both wrong about there being one "reason"?

I speak English(LD). You speak English(RC). The difference between our languages is of the same character as that between a speaker of Spanish and a speaker of French. I say "I" and you correctly read it as referring to lessdazed. You say "I" and I correctly read it as referring to RichardChapell. I have reasons(LD). You have reasons(RC). Do you think that were we perfect at monitoring what we each meant when we said anything and knew the relevant consequences of actions, the two of us would be capable of disagreeing when one of us asserted something in a sentence using the word "moral"? Why?

Or have I misread things?