Hal

I've not read Shadows of the Mind, but I have read the previous book Penrose wrote, "The Emporer's New Mind". As an introduction to some very interesting themes in maths and physics, its brilliant. The chapters on Turing machines, the Church-Turing thesis, and Cantor's hierarchy of infinities are especially superb, and constitute the best 'popular-level' introduction to these topics that I've encountered. His discussion of the Mandelbrot set while defending Platonism is also very interesting, and I think it constitutes a plausible defence of mathematical realism. As a book about consciousness however, I wouldnt be so quick to recommend it. For a better attack on computationalism, I'd recommend anything by Hubert Dreyfus (particularly "What Computers Can't Do"), or (to a lesser extent) John Searle (eg "The Rediscovery of the Mind").

Plato argued that the universe was created, and I doubt it was due to Jewish influence. I think the Mespotamians and Sumerians believed in the creation of the physical universe (which is the same as the Christians, since they believe God/heaven pre-existed the physical spatio-temporal universe created in Genesis - its technically wrong to say that Christians think the world came out of nothing). Most cultures have their own cosmogonies; to claim that its a purely Jewish notion is strange.

Gen X was the last lot, we're generation Y :cool: I disagree. I think young people tend to be disillusioned with the poiltical system for good reason. Perhaps if they didnt live in a country where pretty much all politicians were corrupt, where there was essentially no difference between the major parties, and where the media done their best to reduce political elections to the equivalent of cheering on your team in a game of football, with debate in the popular press/television being little more than the shallow exchange of soundbites, emotionalism, and bad argument, then people would have more interest in the political system. Speaking personally, I've never voted and its unlikely that I will in the near future, but I wouldnt describe myself as politically naive or too lazy. I think that apathy towards the current system is a good thing. Anything that undermines its legitimacy can only be a plus. You cant build a worthless political system and then get upset when people refuse to care about it.

I doubt you believe in a free-press, but it doesnt really matter since its pretty much impossible to censor information these days due to the internet. I suppose you could ban the US press from reporting it, but that wouldnt help you much when its the main story on every non-US media agencies website, and being featured on every political blog on the internet. I suppose you could always threaten to hand out 15 year jail sentences to everyone who talks about it like your government is currently proposing to do to those who report on the Bush administrations (ab)use of domestic surveillence (source: here), but this is around the point where claims to believe in a free press become laughable. The game is pretty much over for those who believe in controlling the free flow of information, and its unlikely that autocratic techniques can achieve more than simply delaying the inevitable. Also, why do you think that Al Jazeera is any more of a propaganda tool than, say, Fox News? I doubt its less biased at any rate; have you ever watched it? You are aware that Islamic regimes have been known to ban it on account of (eg) its being too pro-Israel, yes?

If you want to argue that Objectivism should be mixed with a different philosophy, then surely youre implicitly arguing that Objectivism is either wrong, or incomplete, on some particular point. In that case, wouldnt it be a better idea to debate the particular area where you think Objectivist views need to be replaced/suplanted, rather than the more open-ended question you propose?

This is not what the word 'theory' means in science, despite what the creationists think. There is no reason to doubt that the theory of evolution, or the theory of thermodynamics, are true, yet they remain theories for all that. A theory is just a body of integrated hypothesis'. A good theory is one which is strongly supported by evidence, and which we have firm grounds for believing to be true.

I dont see why this is necessarily impossible. When you learn something, I assume all that happens physically is that your brain moves into a different state, with changes in the connections between your neurons and the like (I dont know the details). If neuroscience were sufficiently advanced, it could be possible to induce these neuronal changes directly by physically pushing things about in the brain, without anything happening in consicousness. I'm speculating here obviously; we dont know enough about how the brain works yet.

Does this mean that, for instance, if I'm of a scientific inclination then I should primarilly be looking for a partner who is an artist? Why shouldnt a person look for someone who is roughly the same as them, rather than going for complementary features? For example, most people choose ther best friends on a basis of similarity rather than complementary. Whats wrong with using the same standard to choose a partner? Suppose a person practiced the (idealised Greek) lifestyle of having sexual intercourse with his close friends of the same sex. Whats the problem here? Theres also the question of whether we are giving practical dating tips for a person living in the modern age, or discussing philosophical principles. Theres no doubt that modern society has certain notions of masculinity and feminity, and as such, a lot of women will go for masculine males whereas males will go for feminine females. But the onus is on you to show that this represents some universal facts about human nature, rather than just being a historically contingent part of modern culture. What we call 'masculine' behavior is probably not universal. The Greeks of Homer would probably consider the average modern man very effemenite, since he shies away from cruelty and doesnt derive pleasure from killing his enemies in glorious battle. You cant focus on one culture and generalise to make descriptive statements about the 'nature' of males and females; an N=1 statistical sample isnt very informative.

Being able to identify an object as a sandbox isnt purely perceptual, since if I havent managed to abstract the features of the previous sandboxes I've seen, I wont know that this object in front of me is a 'sandbox'. Litter trays can look slightly different from each other; knowing that these different objects are all litter trays requires some form of abstraction from percepts. If you replace the cat's litter tray, it should be able to realise that the replacement is still a litter tray, even though it doesnt look exactly the same. Similarly, a cat is able to recognise other cats as being cats, and classify them in a different way from the way it classifies dogs and mice. This again requires abstraction and the ability to categorise objects. My dog food example was admittedly bad, since this can be explained purely via conditioned responses to the smell as you pointed out.

No, of course not - slavery existed back then. The absence of government control is fairly insignificant compared to the fact black people were considered the property of whites. The romanticised views people have of pre 20th century America are baffling, and bordering on racist ("yeah it must have sucked back then if you were black, but who cares about minor details?"). The most free era is almost certainly some point of the 20th century, although I wouldnt like to pick a specific decade. Its hard to say, because the political equality of non-white-males has sadly coincided with the rise of socialism - the earlier back you go, the less government intervention you have, but the worse life would have been if you didnt happen to be both white and male. If I had to pick, I'd go for the 70's or 80's - after the civil rights movement, but before the ridiculous levels of socialism that sprung up in the 90's. Thats not to say that the 70's or 80's were a paradigm of liberty, just that they seem the best of a very very bad bunch.

A concept is just a group of percepts that have been synthesised and retained in the mind. Now, a dog seems able to do this; given the choice between eating a brick and eating a plate of dogfood, he will obviously go for the dogfood. Why? Because he is somehow able to identify dogfood as being 'something I can eat'. In other words, it has abstracted certain features of edible foods it has encountered in the past, and now is roughly able to classify food as being edible or not. There are many other examples like this sort of thing; a housetrained cat knows that it is only meant to poo in the litter tray. And what is a litter tray? Well its something that looks roughly like that. Being able to make percerptual distinctions like this involves something being retained in the mind. In order to be capable of classifying things into different categories, some form of abstraction from previously encoutnered percepts must take place. It seems very obvious that animals do classify objects, and as such, they are abstracting from percepts. Whether or not you want to call this 'concept formation 'seems like a matter of semantics. I suppose you can stipulate that it isnt 'really' a concept unless it exists within a system of language, but this seems rather ad hoc. Think about how you'd actually train an animal to perform an action when it sees a certain type of object, using operant conditioning or whatever. The animal is quite clearly abstrating and retaining something. This is what happens with humans too though. A child doesnt invent concepts out of thin air - it learns its conceptual scheme when it learns its first language, and this scheme preexists its birth. A child will generally classify the world in the same way as people in its surrounding culture, because that it how it has been taught to do things. Colour classification is the most obvious example of this. Children generally dont invent the concept of 'yellowish purple' - they interanlise the same way of breaking up the colour spectrum as those around them. I doubt that a child can just 'go learn' a language, nor can it form the concept 'table' on its own, independently of any kind of reenforcement learning or whatever. If it could, it would be possible for humans to function quite well without being socialised. This does not appear to be the case (eg, feral children). edit: Thats not to say that adults arent capable of challenging the common-language framework. Ayn Rand's objection to the word 'selfish' would be an obvious example of this occurring. But this is not what happens with children who are learning a language/worldview for the first time. Theres no reason at all to think that humans use rules based on necessary and sufficient conditions. To ask the classic Wittgensteinian question, what do all 'games' have in common? What do light blue and dark blue have in common other than that we happen to call them both 'blue'? When we form definitions, we identify the most important attributes. But this does not mean that every single object in this category possesses these attributes, and no other objects outside it. Given the way languages evolve, it would be amazing if there were actually any rigid rules governing the application of our common-language terms. edit: If you think you have discovered an explicit rule for the way we classify things, it would be very easy to program this rule into a computer (dog(x) <=> Legs(x,4) && Barks(x)). If you try this however, you'll almost certainly find that it doesnt work, since your rule will have obvious exceptions and misclassify large numbers of objects.

Is being conscious necessary to have a mind? We often talk about unconscious mental processes for example, and a lot of concepts are formed unconsiously. A computer is capable of integrating two or more similar units, and I see no basis for objecting to the claim it is performing mental processes, regardless of whether its conscious. I mean that they dont integrate their concepts with each other. A computer can see lots of specific trees and form the concept 'tree' by integrating the specific trees it has seen, but this might be the only concept which it has. For humans, we dont possess isolated concepts - our concepts exist within a holistic system of language. A human baby couldnt just learn the word/concept 'tree', without first learning other parts of the English language. This isnt true; computers can form concepts which they werent given explicitly. When youre training a neural network for instance, you have to be careful which test cases you give it because its possible for it to learn a concept completely different from the one you wanted it to (and a concept which may well not exist within the English language). I remember reading about a case where one was being trained to recognise tanks hidden in forests, and it ended up forming the concept of 'tank covered in leaves' or something similar (ie it could correctly identify tanks surrounded by trees, but failed to identify tanks that werent in forests). Yeah, training a NN to recognise trees would be quite trivial these days; an advanced NN actually managed to drive a car across America. They are quite interesting since they represent a very different approach to concept formation than the classical models. Previously it was thought that concept formation was largely a matter of identifying the necessary and sufficient conditions for an object to fall into a category (ie forming the concept of 'tree' would require you to learn a rule that was entirely sufficient to classify trees - ie a set of features which all trees possessed, and nothing apart from trees possessed). The neural network (connectionist) approach throws all this out the window, and operates in an entirely non-rule based manner, using techniques of statistical pattern recognition and 'family resemblence' type approaches instead. A NN couldnt state the explicit rule its using to classify trees as trees (since it isnt actually using one), but then neither could a human. If theres one thing that modern AI has shown, its that terms like 'reasoning with concepts' and 'mental processing' are inherently vague, and need to be sharpened up a lot before you can say that a given entity is or isnt carrying them out.

I think we're going to need to define a criteria for when something is 'operating with concepts'. As far as I'm concerned, a computer running a fairly low level AI program can operate with concepts. For instance, when a neural network has been trained to recognise trees, I think its fair to say that it has formed the concept of 'tree'. Obviously this is very different from the way humans use concepts since a) the computer isnt conscious, and the concepts are isolated and fragmented rather than being integrated within a complete language and form of life (since computers arent embodied). And of course, computers which can using concepts do not have rights.

Luckily philosophers and mathematicians disagreed with your friend when they were (eg) discussing how to formulate the calculus and theory of limits.

How is this any different from Original Sin? As software_nerd said, if everyone is necessarily responsible regardless of what they do, then the concept of responsibility loses its meaning. Ok, I'm responsible. What of it? If my degree of responsibility isnt increased or diminished by my actions, and if the responsibility doesnt imply any moral failing, then why should I care whether I'm responsible or not? What does it even mean to be 'responsible' here?

Not really. There can be good, rational grounds for believing false ideas. We dont even have to dip into exotic scientific refutations of common sense here; a legal trial can find good grounds for beliving that a person is guilty even when the person is innocent. I can have a justified belief that my girlfriend cheated on me, even if she never. And so on. No, I just find them unconvincing. Certain parts of the Newtonian worldview, such as the absoluteness of space and time and the instantaneous propagation of gravitation, have been shown be false. People who want to say that Newtonian mechanics is 'true in context' generally mean that (eg) F=ma gives decent predictions in day to day life. And this is correct. But the Newtonian framework goes deeper than the mathematical statement of the laws. If I postutlated an elaborate theory of gravity which involved invisible goblins with long arms pulling objects towards each other, it may well be that my theory somehow gave rise to mathematical laws which were correct to within some margin of error. But this would not be sufficient to make my theory true, even if the predictions it made were correct, and it could put men on the moon. The truth of the theory would still hinge upon the existence of the entities which it postulated as existing, namely the invisible goblins. Anyway, even if it Newtonian mechanics was just the laws themselves, it would still be odd to say that they were 'true in the context he stated them even if this context was later expanded'. It would be like saying the innocent man was 'guilty in the context of the jury who had seen strong evidence that he committed the crime'. This is just a longwinded way of saying that the jury had good reason to think he was guilty - but the objective fact of the matter is that he was innocent. Truth isnt about what its rational to believe - its about what is true. If this were true, a rational legal system would never come to any incorrect decisions.

Actually, what you said was And this is precisely not the definition that other people are using - its not about 'what you have reason to believe', its about whats true. In the early 18th century, there was no reason to believe that Newtonian mechanics or Euclidean geometry could be incorrect when describing the world, but things changed. I imagine youd say that the people back then were actually certain, but they just turned out to be wrong. Others would say they were wrong to feel certain (or that they werent actually certain). The key issue here is whether being certain about something necessarily guarantees its truth. Objectivists say it doesnt have to, whereas other philosophers say it does. Youre all using different definitions. This is a bad example, since the contrast with mathematical truth is precisely what led people to believe that empirical statements could never be known with absolutely certainty - ie, no matter how verified they were, they were always marginally less certain than the claims of mathematics. The idea was that even if there was no reason to think that an empirical statement could be false, it was possible that it could turn out to be false anyway (like newtonian mechanics). Howeve with mathematical statements like the theorems of Euclidean geometry or artihmetic, so the story goes, its impossible for them to be wrong. No he isnt, hes saying that its always possible that you could be wrong. Hes not saying that you should go around doubting everything for no reason, hes just saying that theres always a chance, however small, that you could be wrong. Its physically possible for my glass to pass through the table when I put it down due to subatomic particle fluctuations, but the odds of this happening are less than 1 in 10^1000. Noone is saying that you should seriously consider the possibility that your glass will pass through the table - they are just saying it isnt impossible (ie the probability is non-zero).

There are some sceptics/nihilists who make that argument. But not everyone who makes that argument is a sceptic/nihilist. No they arent, they are saying that certainty, as defined by them, is impossible. Just because 2 people disagree on whether certainty exists, it doesnt mean they necessarily have different epistemologies - they could just mean different things by 'certainty'. The Objectivist definition of certainty is not the one used by all other people (especially philosophers), since its possible to have Objectivist certainty yet still be wrong. Objectivist certainty is relatively benign, and I dont think most people would have a problem acknowledging it exists. But this often has little to do with what philosophers are arguing about when they discuss whether certainty is possible. The correct response to someone who denies certainty isnt to jump down his throat and call him a sceptic, but to ask him what precisely he means. Depending on how he answers, calling him a sceptic may be justified. edit: for the record, I think the Objectivist definition of certainty is sensible and the one which philosophers since Descartes have tended to use is fairly misleading and pointless.

Not really, its just a different way of defining terms. People who say that you cant be certain are using "certain" to mean 'incapable of being wrong'. Saying that you cant be certain is then just an admission of fallibility; that empirical theories can always be revised in light of future evidence. You can question the wisom of using these definitions (I think theyre pretty silly myself), but it isnt nihilism as such. Noone is saying that you cant be fairly sure about X or that you arent justified in believing X, they are just saying that theres always a possibility, no matter how small, that you could be wrong. Its easy to show mathematically that literal, absolute, infallible certainty is impossible anyway (when you use Bayes Theorem, you cant get your posterior probability equal to 1 if your prior is less than 1, regardless of what evidence you have).

"limiting concept", but this probably isnt what you mean.

In modern (post-Galileo) physics, this is simply wrong; motion isnt an intrinsic characteristic of objects, since it's reference frame dependent. Anything moving at a constant speed can be taken to be at rest by choosing your frame appropriately; theres no such thing as 'objective motion' (or objective rest). The classic example of this is being in a plane. To someone outside the plane, youre moving at 800km/h. But to a person inside the plane, you appear to be stationary. And to someone looking at the plane from mars, you will appear to be moving at over 10000km/h (or whatever speed planet earth is moving relative to mars at). None of these answers is more right than the others. In Aristotlean physics, things were different and motion was objective. But I doubt that Aristotle believed that things have to be moving in order to exist. Why would anyone think that? The Aristotlean terminology here is "efficient cause" for the thing that physically started the motion (eg by giving it a kick). Because its redundant and explains nothing. If everything needs a cause, then the existence-causer needs a cause too. And if you want to say that the existence-causer doesnt need a cause, then theres no reason to assume that the rest of existence does either.

This is terrible, terrible methodology; you cant infer universal statements about human beings/genetics from the behavior of a child 18 months after its birth. The capacity for a child to be influenced by cultural beliefs within the first year of its life is immense. At best, you can conclude that some Western babies are socialised into altruistic practices. This is the sort of poor experimental controls that blighted evolutionary psychology during the first few decades of its existence; I would have thought they'd have learned by now.

Well, it is outside his power to correct. No one individual can change a government/society, although he can influence its long term direction. Its true that a group of people are, in an abstract sense, responsible for their government, but this doesnt mean that everyone is individually responsible. I personally can no more change the government of the UK than I can change the laws of physics. Language is a good analogy here. A language like English or French is the creation of a group of people, and in an abstract sense, these people are responsible for the existence and structure of their language as a whole. But this doesnt mean that John Smith has any real individual power to change the language. Languages do change over time and perhaps he can give it a push in a certain dierction (just like Ayn Rand gave America a slight push towards capitalism) - but he certainly cant change it significantly, and its absurd to hold him directly responsible for the structure of the language which preexisted his birth.

It depends; what does 'being a Jew' mean to you? There are various definitions out there; some people will say a Jew is an active believer in Judaism, whereas others will say you are Jewish iff you have a Jewish mother. Some see Jewishness as a chosen identity, like being a Christian or a Marxist, whereas others see it as being 'given' from birth, like being a woman or a caucasian. What makes you choose to self-identify as a Jew? What does it mean to you? Is it something you are free to reject, or is it given, like being a member of a race (Jewish mother)? In the latter case, theres obviously no conflict with being a Jew and being an Objectivist, since your being a Jew is completely unchosen. In the former case, you'd have to ask slightly deeper questions.

Yes, it is. I do not see raw sensory data (disjoint patches of colour in my visual field) - I see actual objects. This processing of sensory data must be done prior to consciousness. People dont see green patch with bits of brown underneath then interpret this as being a tree - the tree is given to consciousness as an object. What exactly do you mean by 'perception'? I think I recall AR defining it as an integration of raw sensory data (ITOE, first few pages), and if this is the case, it is definitely preconscious. The fact something is automated doesnt mean that it cant be affected by knowledge. Our knowledge must be represented in our brain somehow, which implies that every new thing we learn changes our physical structure. Hence its not absurd to suppose that conscious knowledge can affect nonconscious processing. To take a semi-related example, your body's recovery from disease is 'automated', yet it can still be affected by your conscious attitudes, which is how faith healing and the placebo effect work. Theres not always a rigid boundary between mind and body.