Davy

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Everything posted by Davy

  1. You should read Daniel Kahneman's new book 'Thinking, Fast and Slow'. It's a fascinating (and sometimes disturbing) study of our thinking processes and how intuitive impressions influence our behaviour. To be forewarned is to be forearmed, or as Michael says in his signature - 'know thyself'. ;-)
  2. About 10 years ago I became very depressed as a result of a combination of circumstances involving work and relationships; everything just seemed to go down the pan at once. It was so bad, I could hardly function. On visiting my doctor I was offered counselling/psychotherapy, but declined and said: "nah, just give me some drugs!" Now, I wouldn't necessarily recommend that course of action as a general rule, but given my particular circumstances and the nature of the cause of the depression, I felt it was the right thing to do. After a few weeks, I was back to normal and running on all cylinders. Pyschotherapy isn't such a big thing here in the UK as it is in the USA, although the popularity of Cognitive Behavioural Therapy is increasing, having been adopted by our National Health Service. But as Lutus points out in his article, there is no substantive evidence that any 'talking therapy' has any efficacy beyond that of a placebo. Indeed, it's hard to see how effectiveness could be scientifically measured, given that there is no form of therapy which doesn't depend heavily on the relationship between client and patient, and the mutual belief that such a relationship will be beneficial.
  3. One of many interesting articles on Paul Lutus' site. I've always been fairly ambivalent about the field of Psychology, and always suspected the clinical side was more akin to religion than science. This article has only reinforced that opinion.
  4. Michael, The other side of the coin is that we live on a planet with finite resources, that's a cold hard fact too. I once raised the issue of overpopulation on another Objectivist forum and received a very hostile response, in fact it was nearly enough to turn me off objectivism completely. Some of the responses were truly absurd, such as "we'll move to other planets".
  5. Ok but sticking with deductive logic, it may be true that any conclusions derivable from a set of premises are implied by (or 'contained' in) them, so in that sense the conclusions are necessary, but it doesn't mean that the conclusions are necessarily obvious. If that were the case, they wouldn't be any need for any kind of deductive machinery at all. It isn't at all obvious that, for example, Pythagoras' theorem (or any other theorem of geometry) is merely a long winded way of stating the axioms of Euclid! The discovery of new theorems in mathematics may involve induction, but much of the reasoning is purely deductive, and no-one would deny that new theorems are discovered, not merely justified after they've been found. 'Forward chaining', as used in the 'traditional' Aristotelian logic (and Boolean algebra) is not possible in predicate logic because it is unguided and (as Ba'al pointed out) not guaranteed to terminate. However, in many (maybe most) applications, a mathematical or logical problem is not formulated as a theorem to be proved. Consequents are not given for verification; the task is to determine consequents.
  6. Seems to me like that's a very narrow view of logic. What about inference? surely both are needed for a full account?
  7. Correct, Roger. I used Sommer's cancellation technique given in Kelley's "The Art of Reasoning". It's one of Lewis Carroll's 'Sillygisms', you can find a load more in his 'Symbolic Logic'. The point I was trying to make was that it's impossible to solve this problem, or in fact, any similar problem where it's required to deduce a conclusion from premises, using the predicate calculus. Sure, you can test for validity and consistency, but in order to do that you have to get the conclusion first, by some means other than PL. You could try guessing and then testing for validity, but that's a pretty inefficient way of going about it. Predicate calculus may well be the best tool for exploring the foundations of mathematics (which is what it was invented for), but for philosophy, science and general reasoning, it really sucks (my opinion).
  8. Challenge: solve this logic puzzle using only the predicate calculus. Here are the premises - 1. The only animals in this house are cats 2. Every animal that loves to gaze at the moon is suitable for a pet 3. Animals that I detest are animals that I avoid 4. Only animals that prowl at night are carnivorous 5. No cat fails to catch mice 6. Only the animals in this house ever take to me 7. Kangeroos are not suitable for pets 8. None but carnivores kill mice 9. I detest animals that do not take to me 10. Animals that prowl at night always love to gaze at the moon What is the conclusion?
  9. Interesting site you have there, Roger. By the way, according to mathematician Stanley Burris, who has written a fair bit on Boole's (and other notable 19th Century logician's) logic, says that modern semantics was introduced by Charles Peirce in 1880, although in the Wiki entry on the Square of Opposition it's claimed that Boole argued for universal propositions to lack existential import. Boole's algebra is not the modern boolean algebra, but simply ordinary high school algebra restricted to values of 0 and 1. Burris says: The literature from the late 1800s through the entire 20th century is filled with the wreckage of muffled circumlocutions and failed attempts to explain what Boole was doing. The universal error has been to assume that Boole was using modern semantics for simple class names... Boole used Aristotelian Semantics! For Boole the conversion by limitation argument 'All A is B', therefore 'Some B is A' was correct and proved in both his 1847 and 1854 texts. Not only was his logic misunderstood, but his probability theory (which is covered in "The Laws of Thought") was thought to be wrong. According to David Miller (also mentioned in the Wiki entry on Boole), it's not only not wrong but useful for many problems which conventional probability cannot deal with.
  10. The problem with the Predicate calculus is that it's not very user friendly because it's so far removed from natural language, and I'm pretty sure very few mathematicians use it to derive anything. In fact, you can't actually derive anything at all using the predicate calculus, all you can do is prove a conclusion that's already given. It's much more useful to be able to find what follows from a set of premises. Syllogistic can derive conclusions as well as prove by contradiction.
  11. Thanks Roger. Actually, I just realised that another way of looking at it is to notice that "everything has a cause" is the negation of "something isn't caused", so if A = everything has a cause B = God exists Then we have a standard pattern - if B then ¬A A therefore, ¬B Not sure about your assertion that any hypothetical proposition can be expressed as a categorical proposition though. As I understood it, a conditional proposition isn't quite the same as a hypothetical, or perhaps I'm thinking of a hypothetical as a so-called 'material' conditional.
  12. Here's another challenge for Aristotle's logic: Everything has a cause (premise 1) If God exists, Then something isn't caused (namely, God) (premise 2) Therefore, God doesn't exist (conclusion). The problem is that premise 2 has a quantified term in the consequent of the hypothetical.
  13. Hi Adam, I just watched the documentary - ugh. Ba'al, you're attacking a straw man. Where is the "nonsense"? I never said I believed QM is wrong, and of course you can't argue with results, but it's a matter of interpretation, which you seem to think is irrelevant. Einstein said "God does not play dice". I guess he was talking nonsense too...
  14. It seems to me that you can't avoid some kind of philosophical position; some interpretation is always implied. By advocating "shut up and calculate", with regard to QM, doesn't that imply that the universe is nothing but a mathematical structure? that's absurd. The physicists who pioneered QM seem to have dogmatically rejected identity, causality and non-contradiction. Other interpretations (such as that of De Broglie) were met with unreasonable hostility. One of my pet peeves is the way that the new age brigade have latched on to this interpretation and used it to peddle their bullshit. In one of the replies to that article, Dr Pamela Gerloff says: In my worldview, *nothing* is "definitely real." Everything I experience in the external world is of my own interpretation and construction. Everything in life is subjective. (Even scientists have noticed that the observer influences whether a subatomic entity appears as a wave or a particle, so this part should not really seem so strange.) So you create your own reality; QM proves it!
  15. Ba'al, I'm not sure what you mean by 'philosophical purity'. Do you think that (some) Objectivists are misplaced in their criticism of modern physics, or do you just think it's irrelevant?
  16. I haven't read the book, but Floit doesn't seem to be suggesting that he is merely advancing an alternative theory: "With this book, I dispute those EPR-Bell proofs with simple logic, and provide in this book the experiments that will demonstrate which is correct." Maybe the title is misleading, in the same way that saying Newtonian mechanics is "wrong" would be misleading. Newton wasn't wrong, it's just that his model turned out to be valid only within a limited domain, so the theory was incomplete rather than wrong. In any case, no-one is disputing that the mathematical machinery of QM is not correct (it's amazingly accurate), but there is much disagreement regarding the interpretations (what are the wider implications for the nature of reality). The wikipedia entry on interpretations of quantum mechanics says: No experimental evidence exists that distinguishes among these interpretations. To that extent, the physical theory stands, and is consistent with itself and with reality; difficulties arise only when one attempts to "interpret" the theory. Nevertheless, designing experiments which would test the various interpretations is the subject of active research.
  17. Is the title of this book. I know much of modern physics has been criticised by the objectivist community, so wondering whether anyone's read it? (I haven't, yet) the web site referred to doesn't exist unfortunately. I know very little about QM, but the concept inherent in the Copenhagen interpretation (that randomness is "out there" and not a function of our knowledge) just seems wrong to me.
  18. Yes, it seems that multiple and nested quantifiers are incapable of being expressed... Another example: how would express the concept of a mathematical limit without using the predicate calculus? I'm not even sure that Sommer's term logic could do that.
  19. I haven't read Veatch's book but it sounds interesting. I must say though, that I'm having a hard time understanding the difference between a logic of "what is" and the modern logic of relations (predicate calculus). How do you know what anything IS, except in terms of its relations with other things? It seems to me that the Aristotelian logic can be seen as logic of relations between classes, but those kinds of relations are not the only kind. How, for example, would you express "Everyone falls in love with someone on some enchanted evening" using the traditional syllogism?
  20. Couldn't agree more. Logic doesn't come naturally and kids should be taught early (it should be on a par with the 3 Rs) like in the days of the Trivium.
  21. The Term logic developed by Sommers in recent decades is at least as powerful as predicate logic, see "Something to Reckon With". Really? and how do you know that? Which definition was I appealing to? Physicist E.T. Jaynes has written extensively about what he calls "the mind projection fallacy" - the tendency to assume that lack of knowledge about how things really are as meaning that they're indeterminate. In his book "Probability Theory: The Logic of Science" in a section titled "But what about quantum theory?", Jaynes writes:
  22. David Harriman discusses this in his ARI lecture "The Crisis in Physics—and Its Cause". I'm not entirely convinced by his argument though.
  23. hmm.. well I haven't given it a great deal of thought (hey, it's Friday evening and I've had a couple of beers), but it seems to me that it's somehow related to the "analytic-synthetic" distinction. Is it the case that there are truths which can be known independently of empirical (scientific) investigation? if yes, it implies that there ARE "analytic" truths - true by virtue of meaning alone. But ultimately there is no such distinction (between "analytic" and "synthetic"). So a philosophy cannot be completely independent of empirical evidence.
  24. Interesting point. I suppose it depends on how important the premise is, in terms of how many other premises depend on it. "tabula rasa" isn't what you'd call an axiom of objectivism, is it? Surely a philosophy shouldn't be dependent to such an extent on empirical evidence, otherwise, doesn't it become a science?
  25. Ok, well my point was more about the lack of reflexive thinking which can lead to self-refuting arguments. Some commentators have suggested that the results of quantum physics imply that the 'old' logic is somehow false or incomplete, yet they are using it in order to come to that conclusion. I'm curious as to what you mean by "Indeterminacy exists "in reality"". Indeterminacy is a function of our knowledge (or lack of it), but it seems to me that you're claiming that it's an inherent property of an object.