J. Bradford DeLong said in reply to PaulC…:
Re: "'Brad Delong, to an incorrect conclusion about which direction he was facing, it follows that pure reason can never be a source of knowledge.' I missed the part where Brad DeLong claimed that reason could never be a source of knowledge."
So did I. But don't be too hard on Landsburg. He's just a jumped-up monkey...
Responder "Peter Parker" on Gene Callahan's blog provides the response to Callahan below (which Callahan replies to with either complete misunderstanding, or with some very heavy sarcasm-- hard to say which). I think this is the clearest statement yet, in this blog-vs-blog debate, on the distinction between Nagel's "a priori teleology" and the proposition that all of our reasoning faculties come from evolution, and accretions of social learning and structure laid atop evolution.
I understand your reading of Nagel to be the following: Nagel argues that he possesses an ability, Reason, which allows him to recognise truth directly - in this case, the truth he recognises ("grasps directly") is that two contradictory things cannot be true at the same time. Further, this ability to recognise a logical truth puts him in contact with "the rational order of the world".
I think the materialist counter-argument is that in recognising this truth what Nagel is doing is slightly re-purposing mental circuits that evolved to make logical deductions about the world (I thought that there was one lion in the cave, I just saw two lions come out, I now know I must be cautious since I was wrong about my first belief). This type of reasoning is commonly observed in animal experiments.
This reasoning has well defined failure modes (like our lack of understanding of probability, or the difficulty we have in reasoning about the properties of aggregates vs individual parts) that are consistent with the idea that our thinking is an extension of heuristics built around spatial and visual metaphors that evolved to help us survive, more than some privileged access to a world of pure reason.
More, our ability to press these mental models to alternative service has been greatly stretched by such things as quantum mechanics, where our intuition fails utterly. Our ability to progress here depends on slowly building tools (mathematics) over a long time to help compensate for the deficiencies in our raw thinking ability. This tool building is an essentially social enterprise much bigger than a single human brain."
Anderson said in reply to Thehaymarketbomber…:
Let's not stop with relativity.
Nagel should be arguing that the theory of natural selection is so brilliant, so contrary to the basic patterns of human thought, that creatures which merely evolved could not have come up with it.
Hence, the very existence of Darwin's theory proves creationism.
Well on the one hand, the a priority of geometry even tripped up Immanuel Kant, and he's one of the smartest people who ever lived. But on the other hand, the non-necessity of any particular geometry has been known for a long, long time--It's on Wikipedia and everything--and in the year 2012 there is no excuse to list a geometric "fact" in an inventory of a priori knowledge. This just isn't advanced stuff, people. This is undergraduate History of Philosophy. And Paul Dirac certainly did not predict the positron through "pure reason." God help us. I will bet any money that his predictions were informed by empirical observations. That kind of precludes "pure reason" by definition.
I may have wondered what kind of conversations would erupt in the quiet dark, laden with cannabis haze, if laser Floydd had a malfunction at the planetarium . I shall wonder no more.
I wonder what Nagel thinks happened... Is he an animist? Does he believe that all things are endowed with transcendent knowledge of the absolute, or was it first implanted with the appearance of the nematode? Cockroach? Chimpanzee? What is this strange plan whereby God set in motion the development, by mutation and natural selection, the gradual evolution of massively parallel physical signal processing automatons capable of phenomenal computation and self-serving environmental manipulation, but without the ability to process the idea of self or connect to Platonic forms, a skill so special so as only to be achievable via godlike magic, deposited on the awaiting neurological seat of conciousness at the very last moment of evolutionary history? And then, why the grey glop in the first place, if we are bestowed with such incredible, transcendent magical powers?
The soul, indeed, appears to be the last bastion of the ever retreating armies of God in the war against science for the ontological territory. The rise of the machines, presumably, will deal the final blow.
Phil Koop said...
Reading through the comment threads of Landsburg and Callahan, it seems that neither they nor there commenters have grasped the point. They all seem to think that you have myopically seized upon a particular error that Nagel happened to make, criticizing an example that was poorly chosen and mistaking it for the argument itself.
None of them seem to understand that you yourself are merely presenting an example; that it was chosen by the other side is apposite but not essential. None seem to understand that this example also merely illustrates a point: that beliefs are only "contradictory" inasmuch as we perceive them to be so; that this perception is as prone to error as any other; and that we cannot with certainty distinguish a logical inference that happens to be wrong from one that happens to be right. Theirs is an epistemology that assumes its conclusion.
Somehow or other you have got to make the point more plainly. But don't ask me how.
I have some E. coli that also appear to reason like winged angelic beings. When the concentration of Oxygen in their environment decreases they know that it means that they are traveling away from a source of Oxygen. So they try to change direction in an attempt to move towards the source of Oxygen. One wonders how they gained access to such eternal truths.
Gibbon1 said in reply to D. C. Sessions...
I think we all agreed around the time that Friedrich Wöhler found he could manufacture urea from scratch without the necessity of a dogs kidneys that there isn't anything special about the chemistry of living tissue. Should be obvious at that point, the brain is mechanistic as well.
In any event Nagel is rooting around in the same cesspit that Marvin Minsky and his students lost their way in from the 1960 onwards, which is reason as we know it isn't fundamental to intelligence, and the information processing done by brains is radically different than what turning machines naturally implement. To wit, the mind doesn't do symbolic reasoning. Or more carefully it's not what goes on under the hood.
kharris said in reply to PaulC...
"The application of evolutionary theory to the understanding of our own cognitive capacities should undermine… them…."
"This seems to be Nagel's main thesis, and it's not convincing. The claim is only self-evident if you equate the imperfect with the useless."
Yup. Maybe mostly because I am annoyed with his rhetorical choices, but it seems to me Negal left a big chunk out of his view of his entire subject. There is no learning in it, no process. There is only reason or heuristic, already in place and put to use. Learning involves approximation. Put what has been learned to use in reason or rule-of-thumb, the learning was still arrived at through approximation. Say "transcendent" all you want, but we feed both reason and rule imperfect information. Transcend that, ya mook!
Nagel's claim that an imperfect source cannot arrive at a transcendent result is, in fact, an very old argument, an argument for the existence of god. That he has employed it in a particular context without making a big deal about the religious origin of his argument doesn't change that. Both sides of the debate over that theological argument - including the side that opposes Nagel - are in play here. Does he address that debate or answer the objections of the other side? Like other commenters here, I haven't read the book, so I don't know. However, to the extent that Nagel pretends he is offering something new, he ought to be held to account for it. It would seem like dog-whistle scholasticism to leave the history of his argument unaddressed.
By the way, my annoyance at his rhetorical stance (aside from his whole "watch me argue like a philosopher schtick, which I can't ding him for, though I'd like to) is that waving around notions like "transcendence" is just so conveniently distracting. And I think I detect transcendence being snuck in, merely Nagel's prior. Only if reason is all he claims for it can he also claim reason to be transcendent. If monkey brains can't be relied upon to know that we are, in fact, employing monkey brains - but Nagel can't prove we don't have monkey brains - then he also can't know that there is anything like transcendence. He might just be employing a fallible monkey brain that is tricked into seeing transcendence. Huge question begging going on here, isn't there?
Ugh. Nagel seems to be saying that the evolutionary position means that we cannot be sure that a priori judgments can be true, and then says that evolutionary theory is an a priori judgment.
Science as it is practiced in the 21st century is a systematic framework of a POSTERIORI judgments that are held as true PROVISIONALLY until demonstrated otherwise a posteriori.
Philosophy is now the handmaiden of science and that makes philosophers bitchy.
Why is it so often so incredibly hard to admit that the whole world won't fit in your head? Even tougher than becoming comfortable with the notion that one is a skin bag full of unpleasantly textured glop, generally. (That the glop is textured by happen-stance seems to be bitter olive in the martini of reality.)
If you want to believe in inherent accuracy of anything, you have to believe the thing accurately represented fits in the thing with the inherent accuracy, and instead of being turtles all the way down, it's increasingly expansive over-minds all the way up.
Since the world has billions of other minds in it, just as good as yours, and which you'd supposedly have to encompass to have inherent certainty about other people, the problem of inherent accuracy explodes into recursive nonsense.
The whole point of facts is that they're not in any one person't head, that the process of labelling something a fact works no matter who is doing it. Nagel appears to be darkly unhappy with that definition of fact.
The word "reductionist" always raises my hackles. As far as I know, It's one of those terms (like secular humanist) exclusively applied to opponents (not that there is anything wrong with being a secular humanist). Does any living scientist claim to be a reductionist? I can imagine someone at one time (maybe Leibniz) imagining that the failure to understand everything was just a failure to understand the underlying rules. But it really only takes a smattering of the previous century's mathematics and/or computation theory to see how little you really understand just by pinning down the underlying axioms and inference rules.
Obviously there will be no "transcendent self-understanding" that is reductionist. There will not even be a reductionist understanding of Wolfram's Rule 110 automaton for instance--though its rules could be scrawled in purple crayon inside a matchbook cover--since it's known to be Turing complete. I'm not even sure what a reductionist understanding is. I imagine it might be something like superposition of waves or of potentials in a resistor circuit. This kind of thing works on linear systems, and doesn't help much beyond that. Most systems can only be predicted with any precision by simulating them. Actual human "understanding" tends to consist of models with simplifying assumptions and is always a partial understanding that acknowledges that the whole is more than the sum of parts. Nobody in the 21st century who has made a serious attempt to understand anything is reductionist.
This isn't to say there will be no scientific understanding of consciousness, just not a reductionist one. I think we're currently far from that too. But systems of discrete logic already defy human analysis. I don't see why they shouldn't be conscious too. And the day that one tells me that it is, and acts like other conscious entities, I would find this evidence more compelling than any contrived "Chinese room"-style argument to the contrary.
Actually, it struck me that humans will probably be arguing over whether an AI is truly conscious until the day we make one with sufficiently superhuman intelligence to formulate an argument that human philosophers will accept.
Matt McIrvin said...
Isn't Nagel's argument essentially the same as C. S. Lewis's argument for the existence of the supernatural? I think Lewis argued that if reasoning is just the working-out of laws of physics rather than some transcendent contact with reality, then we have no reason to trust that our reason is telling us reliable things, including the reasoning that tells us that reasoning is just the working-out of laws of physics; therefore materialism is incoherent.
My first stab as a counterargument was to invoke evolution as a process that drives reasoning toward survival-usefulness, but I guess Nagel is preemptively cutting that off because evolution is not teleological (maybe? I suppose I need to read the book to be sure).
I know some people have argued that the effectiveness of reason mysteriously exceeds the realm in which it's useful to survival, but that could be considered a mysterious property of the external universe rather than of the origin of reason: for some reason the universe is accessible to reasoned investigation.