65 ideas
| 5728 | The concept of truth was originated by the senses [Lucretius] |
| Full Idea: The concept of truth was originated by the senses. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], IV.479) | |
| A reaction: This is a refreshing challenge to the modern view of truth, which seems entirely entangled with language. Truth seems a useful concept when discussing the workings of an animal mind. As you get closer to an object, you see it more 'truly'. |
| 6346 | The main epistemological theories are foundationalist, coherence, probabilistic and reliabilist [Pollock/Cruz] |
| Full Idea: The most familiar epistemological theories are foundation theories, coherence theories, probabilistic theories, and reliabilist theories. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], Pref) | |
| A reaction: A helpful list. Reliabilism is now the dominant externalist theory. Probability theories will centre on Bayes' Theorem (Idea 2798). The authors want an internalist theory that includes perceptions as well as beliefs. I currently favour coherence. |
| 6351 | Most people now agree that our reasoning proceeds defeasibly, rather than deductively [Pollock/Cruz] |
| Full Idea: One of the most important modern advances in epistemology was the recognition of defeasible reasons; it is now generally acknowledged that most of our reasoning proceeds defeasibly rather than deductively. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §1.2) | |
| A reaction: I agree totally. This is why fallibilism is clearly a correct position in epistemology (e.g. Ideas 2736 and 2755). Deduction is not the only grounds given for certainty - there are rationalist foundations (Descartes) and empiricist foundations (Moore). |
| 6374 | To believe maximum truths, believe everything; to have infallible beliefs, believe nothing [Pollock/Cruz] |
| Full Idea: If we want an agent to believe as many truths as possible, this could be achieved by simply believing everything; if we want an agent to have only true beliefs, this could be achieved by believing nothing. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §6.6) | |
| A reaction: I like this. It highlights the pragmatic need for a middle road, in which a core set of beliefs are going to be approved of as 'knowledge', so that we can get on with life. This has to be a social matter, and needs flexibility of Fallibilism. |
| 6355 | Direct realism says justification is partly a function of pure perceptual states, not of beliefs [Pollock/Cruz] |
| Full Idea: We defend a version of direct realism, saying that justification must be partly a function of perceptual states themselves, and not just a function of our beliefs about perceptual states. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §1.5.3) | |
| A reaction: Judgement suggests that perceptual states give good justification about primary qualities (like mass or shape), but not of secondary qualities (like smell or colour). Perceptions can be downright misleading. |
| 6359 | Phenomenalism offered conclusive perceptual knowledge, but conclusive reasons no longer seem essential [Pollock/Cruz] |
| Full Idea: Phenomenalism offered the prospect of explaining perceptual knowledge within a framework that recognised only conclusive reasons; once it is acknowledged that at least induction uses nonconclusive reasons, it is no longer needed. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §2.3.3.2) | |
| A reaction: I'm not sure that that is the only motivation for phenomenalism, which seemed to be attempting to get as close to 'reality' as intellectual honesty would allow. I certainly favour the modern relaxed attitude to knowledge, which needn't be 'conclusive'. |
| 6366 | Perception causes beliefs in us, without inference or justification [Pollock/Cruz] |
| Full Idea: Perception is a causal process that inputs beliefs into our doxastic system without their being inferred from or justified on the basis of other beliefs we already have. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §3.2.3) | |
| A reaction: This topic is much discussed (e.g. by MacDowell). I don't see how something is going to qualify as a 'belief' if it doesn't involve concepts and propositions. The point that we are caused to have many of our beliefs (rather than judging) seems right. |
| 6362 | Sense evidence is not beliefs, because they are about objective properties, not about appearances [Pollock/Cruz] |
| Full Idea: We think it is a mistake to suppose that the evidence of our senses comes to us in the form of beliefs; in perception, the beliefs we form are almost invariably about the objective properties of physical objects - not about how they appear to us. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §2.5.5) | |
| A reaction: The tricky word here is 'evidence'. At what point in the process of perception does something begin to count as evidence? It must at least involve concepts (and maybe even propositions) if it is going to be thought about in that way. |
| 5729 | If the senses are deceptive, reason, which rests on them, is even worse [Lucretius] |
| Full Idea: The structure of your reasoning must be rickety and defective, if the senses on which it rests are themselves deceptive. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], IV.518) | |
| A reaction: This strikes me as one of the most basic tenets of empiricism. It denies the existence of 'pure' reason, and instead asserts that it is built out of complex and abstracted sense experience, which makes it ultimately a second-class citizen. |
| 5702 | The senses are much the best way to distinguish true from false [Lucretius] |
| Full Idea: What can be a surer guide to the distinction of true from false than our own senses? | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.700) | |
| A reaction: This doesn't say they are the only guide, which leaves room for guides such as what is consistent or self-evident or inferred. There is enough here, though, to show that the Epicureans were empiricists in a fairly modern way. |
| 6371 | Bayesian epistemology is Bayes' Theorem plus the 'simple rule' (believe P if it is probable) [Pollock/Cruz] |
| Full Idea: Bayesian epistemology is based upon the 'simple rule' (believe P if it is sufficiently probable) and Bayes' Theorem. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §4.3.1) | |
| A reaction: For Bayes' Theorem, see Idea 2798. There is the question of whether the proposition is subjectively or objectively probable (I believe in ghosts, so any shadow is probably a ghost). There is also the problem of objective evidence for the calculation. |
| 6373 | Internalism says if anything external varies, the justifiability of the belief does not vary [Pollock/Cruz] |
| Full Idea: Internalist theories make justifiability of a belief a function of the internal states of the believer, in the sense that if we vary anything but his internal states the justifiability of the belief does not vary. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §5.4.3) | |
| A reaction: This seems to be a nice clear definition of internalism (and, by implication, externalism). It favours externalism. I know my car is in the car park; someone takes it for a joyride, then replaces it; my good justification seems thereby weakened. |
| 6353 | People rarely have any basic beliefs, and never enough for good foundations [Pollock/Cruz] |
| Full Idea: We argue that all foundations theories are false, for the simple reason that people rarely have any epistemological basic beliefs, and never have enough to provide a foundation for the rest of our knowledge. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §1.5.3) | |
| A reaction: Once surprising things start to happen in a film, we rapidly jettison our normal basic beliefs, to be ready for surprises. However, it seems to me that quite a lot of beliefs are hard-wired into us, or inescapably arise from the use of our senses. |
| 6361 | Foundationalism requires self-justification, not incorrigibility [Pollock/Cruz] |
| Full Idea: What foundationalism requires is self-justification, which is weaker than incorrigibility. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §2.5.3) | |
| A reaction: The writers oppose foundationalism, but this remark obviously helps the theory. Bonjour votes for a fallible rationalist foundationalism, and an fallible empiricist version seems plausible (because we must check for hallucinations etc.). |
| 5697 | The only possible standard for settling doubts is the foundation of the senses [Lucretius] |
| Full Idea: If a belief resting directly on the foundation of the senses is not valid, there will be no standard to which we can refer any doubt on obscure questions for rational confirmation. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.422) | |
| A reaction: A classic statement of empiricist foundationalism. The Epicureans don't appear to have any time for a priori truths at all. I wonder if they settled mathematical disputes by counting objects and drawing diagrams? |
| 6357 | Reason cannot be an ultimate foundation, because rational justification requires prior beliefs [Pollock/Cruz] |
| Full Idea: Reasoning, it seems, can only justify us in holding a belief if we are already justified in holding the beliefs from which we reason, so reasoning cannot provide an ultimate source of justification. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §2.1) | |
| A reaction: This sounds slick and conclusive, but it isn't. If we accept that some truths might be 'self-evident' to reason, they could stand independently. And a large body of rational beliefs might be mutually self-supporting, as in the coherence theory of truth. |
| 6363 | Foundationalism is wrong, because either all beliefs are prima facie justified, or none are [Pollock/Cruz] |
| Full Idea: Either no belief is prima facie justified or all beliefs are prima facie justified; …we regard this as a decisive refutation of foundationalism. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §2.5.5) | |
| A reaction: The full text must he examined, but it is not at all clear to me how my belief that quantum theory is correct could be even remotely as prima facie justified as my belief that this is my hand. I don't think basic beliefs need be sharply divided off. |
| 6365 | Negative coherence theories do not require reasons, so have no regress problem [Pollock/Cruz] |
| Full Idea: The regress argument has no apparent strength against negative coherence theories, because they do not require reasons for beliefs. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §3.2.3) | |
| A reaction: A nice point. Such theories endorse Neurath's picture (Idea 6348). On the whole philosophers like positive support for their beliefs, so the rather passive picture of accepting everything unless it is undermined is not appealing. A fall-back position. |
| 6354 | Coherence theories fail, because they can't accommodate perception as the basis of knowledge [Pollock/Cruz] |
| Full Idea: All coherence theories fail, because they are unable to accommodate perception as the basic source of our knowledge of the world. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §1.5.3) | |
| A reaction: An interesting claim, which the authors attempt to justify. They say it is direct realism, because the perceptions justify, without any intervening beliefs. My immediate thought is that they might justify knowledge of primary qualities, but not secondary. |
| 6367 | Coherence theories isolate justification from the world [Pollock/Cruz] |
| Full Idea: The Isolation Argument objects that coherence theories cut justification off from the world. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §3.2.4) | |
| A reaction: I don't see this as a strong objection. Justification can be in the way beliefs cohere together, but the beliefs themselves consist of holding propositions to be true, and truth asserts a connection to the world (I say). |
| 6370 | Externalism comes as 'probabilism' (probability of truth) and 'reliabilism' (probability of good cognitive process) [Pollock/Cruz] |
| Full Idea: There are two major kinds of externalist theory in the literature - probabilism (which expresses justification in terms of probability of the belief being true), and reliabilism (which refers to the probability of the cognitive processes being right). | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §4.1) | |
| A reaction: A useful clarification. Reliabilism has an obvious problem, that a process can be reliable, but only luckily correct on this occasion (a clock which has, unusually, stopped). A ghost is more probably there if I believe in ghosts. |
| 6358 | One belief may cause another, without being the basis for the second belief [Pollock/Cruz] |
| Full Idea: If I fall flat on my back running to a class, my belief that I was late for class may cause me to have the belief that there are birds in the trees, but I do not believe the latter on the basis of the former. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §2.3.1) | |
| A reaction: A nice example, which fairly conclusively demolishes any causal theory of justification. My example is believing correctly that the phone ring is from mother, because she said she would call. Maybe causation is needed somewhere in the right theory. |
| 5727 | Most supposed delusions of the senses are really misinterpretations by the mind [Lucretius] |
| Full Idea: Paradoxical experiences (such a dreams and illusions) cannot shake our faith in the senses. Most of the illusion is due to the mental assumptions we ourselves superimpose, so that things not perceived by the senses pass for perceptions. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], IV.462) | |
| A reaction: Some misinterpretations of the senses, such as thinking a square tower round, are the result of foolish lack of judgement, but actual delusions within the senses, such as a ringing in the ears, or a pain in a amputated leg, seem like real sense failures. |
| 6364 | We can't start our beliefs from scratch, because we wouldn't know where to start [Pollock/Cruz] |
| Full Idea: We cannot forsake all of our beliefs and start over again, because then we could not know how to start. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §3.1) | |
| A reaction: A point with which it is hard to disagree, but even Descartes agreed with it (Idea 3604). Presumably all your beliefs can take it in turn to be doubted, while others are held true, or you can whittle the beliefs which can't be abandoned down to a minimum. |
| 5714 | Even simple facts are hard to believe at first hearing [Lucretius] |
| Full Idea: No fact is so simple that it is not harder to believe than to doubt at the first presentation. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.1022) | |
| A reaction: Hence induction is just 'drumming it in' until you come to believe it. There are good evolutionary reasons why we should be like this, because we would otherwise believe all sorts of silly half-perceptions in the gloaming. |
| 6352 | Enumerative induction gives a universal judgement, while statistical induction gives a proportion [Pollock/Cruz] |
| Full Idea: Enumerative induction examines a sample of objects, observes they all have a property, and infers that they all have that property; statistical induction observes a proportion of the objects having the property, and infers that proportion in general. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §1.4.6) | |
| A reaction: There is also induction by elimination, where it is either p or q, and observation keeps saying it isn't p. A small sample is very unreliable, but a huge sample (e.g. cigarettes and cancer) is almost certain, so where is the small/huge boundary? |
| 6372 | Since every tautology has a probability of 1, should we believe all tautologies? [Pollock/Cruz] |
| Full Idea: It follows from the probability calculus that every tautology has probability 1; it then follows in Bayesian epistemology that we are justified in believing every tautology. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §4.3.1.5) | |
| A reaction: If I say 'a bachelor is a small ant' you wouldn't believe it, but if I said 'I define a bachelor as a small ant' you would have to believe it. 'Bachelors are unmarried' men is a description of English usage, so is not really a simple tautology. |
| 6360 | Scientific confirmation is best viewed as inference to the best explanation [Pollock/Cruz] |
| Full Idea: The confirmation of scientific theories is probably best viewed in terms of inference to the best explanation. | |
| From: J Pollock / J Cruz (Contemporary theories of Knowledge (2nd) [1999], §2.3.3.3) | |
| A reaction: A simple claim, but one with which I strongly agree. 'Inference', of course, implies that there is some fairly strict logical thinking going on, which may not be so. I suspect that dogs can move to the best explanation. It is, though, a rational process. |
| 5718 | The mind is in the middle of the breast, because there we experience fear and joy [Lucretius] |
| Full Idea: The guiding principle of the whole body is the mind or intellect, which is firmly lodged in the mid-region of the breast. Here is felt fear and alarm, and the caressing pulse of joy. Here, then is the seat of the intellect and mind. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.140) | |
| A reaction: Even by this date thinking people were not clear that the mind is in the brain. They paid insufficient attention to head injuries. The emotions are felt to have a location, but intellect and principles are not. |
| 5717 | The mind is a part of a man, just like a hand or an eye [Lucretius] |
| Full Idea: First, I maintain that the mind, which we often call the intellect, the seat of guidance and control of life, is part of a man, no less than hand or foot or eyes are parts of a whole living creature. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.95) | |
| A reaction: Presumably Lucretius asserts this because some people were denying it. Sounds like common sense to me. The only reason I can see for anyone denying what he says is if they are desperate to survive death. |
| 21387 | The separate elements and capacities of a mind cannot be distinguished [Lucretius] |
| Full Idea: No single element [of the soul] can be separated, nor can their capacities be divided spatially; they are like the multiple powers of a single body | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.262), quoted by A.A. Long - Hellenistic Philosophy 2.7 | |
| A reaction: It is interesting that this comes from someone with a strongly physicalist view of the mind (though not, if I recall, focusing on the brain). He is still totally impressed by the unified phenomenology of mental experience. He is an empiricist. |
| 5709 | The actions of the mind are not determinate and passive, because atoms can swerve [Lucretius] |
| Full Idea: The fact that the mind itself has no internal necessity to determine its every act and compel it to suffer in helpless passivity - this is due to the slight swerve of the atoms at no determinate time or place. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.294) | |
| A reaction: No one likes this proposal much, but it is very intriguing. The Epicureans had seen a problem, one which doesn't bother me much. If, nowadays, you are a reductive physicalist who believes in free will, you have a philosophical nightmare ahead of you. |
| 5695 | Only bodies can touch one another [Lucretius] |
| Full Idea: Nothing can touch or be touched except body. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.303) | |
| A reaction: This is the key objection to interactionism, and the main reason why the atomists have a thoroughly material view of the mind. It is an induction from a very large number of instances, but the argument is not, of course, conclusive. |
| 5711 | The earth is and always has been an insentient being [Lucretius] |
| Full Idea: The earth is and always has been an insentient being. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.658) | |
| A reaction: The fact that Epicurus needs to deny this shows that some idea close to panpsychism must still have been around in his time. He is discussing gods at the time, so maybe pantheism was the view being attacked, but that is a subset of panpsychism. |
| 5712 | Particles may have sensation, but eggs turning into chicks suggests otherwise [Lucretius] |
| Full Idea: There is the possibility that particles have senses like those of an animate being as a whole, …but from the fact that we perceive eggs turning into live fledglings, we may infer that sense can be generated from the insentient. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.914) | |
| A reaction: He gives other arguments for his view. The egg example is not a strong argument, but is precisely our puzzle of how consciousness can emerge from the process of evolution, and natural selection makes dualism look unlikely. |
| 5719 | The mind moves limbs, wakes the body up, changes facial expressions, which involve touch [Lucretius] |
| Full Idea: Mind and spirit are both composed of matter, as we see them propelling limbs, rousing the body from sleep, changing the expression of the face, and guiding the whole man - activities which clearly involves touch, which involves matter. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.164) | |
| A reaction: This is the inverse of Descartes' interaction problem, and strikes me as a straightforward common sense truth. However, if you believe in spiritual gods, this gives you a model for the interaction (however mysterious) of matter and spirit. |
| 5724 | Lions, foxes and deer have distinct characters because their minds share in their bodies [Lucretius] |
| Full Idea: Why are lions ferocious, foxes crafty, and deer timid? It can only be because the mind always shares in the specific growth of the body according to its seed and breed. If it were immortal and reincarnated, living things would have jumbled characters. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.743) | |
| A reaction: A nice argument which I have not encountered in modern times. Of course, even Descartes admits that the mind is intermingled with the body, but it seems that the essential character of a mind is dictated by the body. |
| 5713 | You needn't be made of laughing particles to laugh, so why not sensation from senseless seeds? [Lucretius] |
| Full Idea: One can laugh without being composed of laughing particles, ..so why cannot the things that we see gifted with sensation be compounded of seeds that are wholly senseless? | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.988) | |
| A reaction: Lovely argument! You might feel driven to panpsychism in your desperation to explain the 'weirdness' of consciousness, but it would be mad to attribute laughter to basic matter, so comedy has to 'emerge' at some point. |
| 14080 | Are causal descriptions part of the causal theory of reference, or are they just metasemantic? [Kaplan, by Schaffer,J] |
| Full Idea: Kaplan notes that the causal theory of reference can be understood in two quite different ways, as part of the semantics (involving descriptions of causal processes), or as metasemantics, explaining why a term has the referent it does. | |
| From: report of David Kaplan (Dthat [1970]) by Jonathan Schaffer - Deflationary Metaontology of Thomasson 1 | |
| A reaction: [Kaplan 'Afterthought' 1989] The theory tends to be labelled as 'direct' rather than as 'causal' these days, but causal chains are still at the heart of the story (even if more diffused socially). Nice question. Kaplan takes the meta- version as orthodox. |
| 6611 | One man's meat is another man's poison [Lucretius] |
| Full Idea: What is food to one may be literally poison to others. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], IV.638) | |
| A reaction: This seems to be the origin of the well-known saying. This is not relativism of perception, but a relativism of how individuals actually respond to the world. It sums up the position with, say, the operas of Wagner. |
| 5730 | Our bodies weren't created to be used; on the contrary, their creation makes a use possible [Lucretius] |
| Full Idea: Nothing in our bodies was born in order that we might be able to use it, but the thing born creates the use. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], IV.834) | |
| A reaction: This remark (strongly opposed to Aristotle's view of human function and nature) raises the obvious question of why the body is so very useful for staying alive. Most of its uses are not random. Lucretius would abandon this view if he read Darwin. |
| 5726 | The dead are no different from those who were never born [Lucretius] |
| Full Idea: One who no longer is cannot suffer, or differ in any way from one who has never been born. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.867) | |
| A reaction: There is a special kind of pain in being poor if you were once rich, which is not suffered by those who experience only poverty. Lucretius is right, but we are concerned with how we feel now, not with how we won't feel once dead. |
| 5705 | Nature only wants two things: freedom from pain, and pleasure [Lucretius] |
| Full Idea: Nature only clamours for two things, a body free from pain, a mind released from worry and fear for the enjoyment of pleasurable sensation. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.21) | |
| A reaction: I can't help agreeing with those (like Aristotle) who consider this a very demeaning view of human life. See Idea 99. Bentham agrees with Lucretius (Idea 3777). I think they are largely right, but not entirely. Other motives are possible than sensations. |
| 5716 | Nature runs the universe by herself without the aid of gods [Lucretius] |
| Full Idea: Nature is free and uncontrolled by proud masters and runs the universe by herself without the aid of gods. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.1094) | |
| A reaction: A nice remark. This apparent personification of nature implies the application of laws to an essentially passive reality. See Idea 5442 and Nature|Laws of Nature|Essentialism for a different view. |
| 5704 | There can be no centre in infinity [Lucretius] |
| Full Idea: There can be no centre in infinity. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.1069) | |
| A reaction: This is highly significant, because if we can establish that the universe is infinite (as Epicurus believes), it follows that the human race cannot be at the centre of it, as the Ptolemaic/medieval view proposed. |
| 5703 | The universe must be limitless, since there could be nothing outside to limit it [Lucretius] |
| Full Idea: The universe is not bounded in any direction. If it were, it would necessarily have a limit somewhere, but a thing cannot have a limit unless there is something outside to limit it. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.959) | |
| A reaction: This is a subtler argument than the mere enquiry about why you would have to stop at the end of the universe. It still seems a nice argument, though Einstein's curvature of space seems to have thwarted it. |
| 5693 | Everything is created and fed by nature from atoms, and they return to atoms in death [Lucretius] |
| Full Idea: The ultimate realities of heaven and the gods are the atoms, from which nature creates all things and increases and feeds them, and into which, when they perish, nature again resolves them. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.46) | |
| A reaction: Sounds right to me. Nothing in modern particle theory and string theory has refuted this claim. But what makes the atoms move, and what makes them combine in an orderly way? Is the orderliness of atoms made of atoms? Essences? |
| 5701 | If an object is infinitely subdivisible, it will be the same as the whole universe [Lucretius] |
| Full Idea: If there are no atoms, the smallest bodies will have infinite parts, since they can be endlessly halved. ..But then there will be no difference between the smallest thing and the whole universe, as they will equally have infinite parts. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.620) | |
| A reaction: Another argument which remains effective even now. There must surely (intuitively) be more divisions possible in a large object than in a small one? Unless of course there were many different sizes of infinity…. See Cantor. |
| 5708 | In downward motion, atoms occasionally swerve slightly for no reason [Lucretius] |
| Full Idea: When atoms are travelling straight down through empty space by their own weight, at quite indeterminate times and places they swerve ever so little from their course. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.217) | |
| A reaction: Never a popular theory because it seems to breach the Principle of Sufficient Reason (Ideas 306 + 3646). This seems to be the beginning of a strong need for the concept of free will, and an underlying explanation. Most thinkers put mind outside nature. |
| 17004 | Nothing can break the binding laws of eternity [Lucretius] |
| Full Idea: Nothing has power to break the binding laws of eternity. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], 5.56) | |
| A reaction: This seems to be virtually the only remark from the ancient world suggesting that there are 'laws' of nature, so I'm guessing it is a transient metaphor, not a theory about nature. 'Even the gods must bow to necessity'. |
| 5706 | Atoms move themselves [Lucretius] |
| Full Idea: Atoms move themselves. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.133) | |
| A reaction: Something has to move itself, I suppose, but then that could be psuché, giving us free will (see Idea 1424). Why does Epicurus need the 'swerve' if atoms are self-movers? See Idea 5708. |
| 5696 | If there were no space there could be no movement, or even creation [Lucretius] |
| Full Idea: We see movement everywhere, but if there were no empty space, things would be denied the power of movement - or rather, they could not possibly have come into existence, embedded as they would have been in motionless matter. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.342) | |
| A reaction: This still seems a good argument, if reality is made of particles. People can move in a crowd until it becomes too dense. |
| 5700 | It is quicker to break things up than to assemble them [Lucretius] |
| Full Idea: Anything can be more speedily disintegrated than put together again. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.558) | |
| A reaction: Clearly the concept of entropy was around long before anyone tried to give a systematic or mathematical account of it. |
| 5698 | We can only sense time by means of movement, or its absence [Lucretius] |
| Full Idea: It must not be claimed that anyone can sense time by itself apart from the movement of things or their restful immobility. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.465) | |
| A reaction: This seems a remarkably Einsteinian remark, though he is only talking of the epistemology of the matter, not the ontology. We are not far from the concept of space-time here. |
| 5715 | This earth is very unlikely to be the only one created [Lucretius] |
| Full Idea: It is in the highest degree unlikely that this earth and sky is the only one to have been created. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.1057) | |
| A reaction: I can only admire the science fiction imagination of this, which roughly agrees with the assessment of modern cosmologists. We think imagination was cramped in the ancient world, and now wanders free - but that is not so. |
| 5694 | Nothing can be created by divine power out of nothing [Lucretius] |
| Full Idea: In studying the workings of nature, our starting-point will be this principle: nothing can ever be created by divine power out of nothing. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.152) | |
| A reaction: This claim seems to cry out for a bit of empiricist caution. What observation has convinced Lucretius that creation out of nothing is impossible? The early Christians switched to the view that divine creation is 'ex nihilo' - out of nothing. |
| 5699 | If matter wasn't everlasting, everything would have disappeared by now [Lucretius] |
| Full Idea: If the matter in things had not been everlasting, everything by now would have gone back to nothing, and the things we see would be the product of rebirth out of nothing. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], I.544) | |
| A reaction: See Idea 1431, which is Aquinas's Third Way of proving God. Aquinas thinks there must be a necessary being outside of the system, but Lucretius thinks there must be some necessary existence within the system (as Hume had suggested). |
| 5707 | The universe can't have been created by gods, because it is too imperfect [Lucretius] |
| Full Idea: The universe was certainly not created for us by divine power: it is so full of imperfections. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.180) | |
| A reaction: This is certainly a problem if God is 'supremely perfect', as Descartes proposed, because then the universe would also have to be supremely perfect. See Idea 2114 for a possible answer from Leibniz. Hume agrees with Epicurus about design. |
| 5710 | Gods are tranquil and aloof, and have no need of or interest in us [Lucretius] |
| Full Idea: The nature of deity is to enjoy immortal existence in utter tranquillity, aloof and detached from our affairs. It is free from all pain and peril, strong in its own resources, exempt from any need of us, indifferent to our merits and immune from anger. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], II.652) | |
| A reaction: This seems to be the seed of late seventeenth century deism - the idea of a Creator who is now absent, and ignores our prayers. At that time 'Epicurean' became a synonym for atheist, but Epicureans never quite reached that point. |
| 5731 | Why does Jupiter never hurl lightning from a blue sky? [Lucretius] |
| Full Idea: Why does Jupiter never hurl his thunderbolt upon the earth and let loose his thunder out of a sky that is wholly blue? | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], VI.400) | |
| A reaction: Nice question! It really doesn't take very much to see through superstition, and the fact that most people believed such things shows how staggeringly uncritical they were in their thinking, until philosophers appeared and taught them how to reason. |
| 5722 | For a separated spirit to remain sentient it would need sense organs attached to it [Lucretius] |
| Full Idea: If spirit is immortal and can remain sentient when divorced from our body, we must credit it with possession of five senses; but eyes or nostrils or hand or tongue or ears cannot be attached to a disembodied spirit. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.624) | |
| A reaction: This is a powerful argument against immortality. If you are going to see, you must interact with photons; to hear you must respond to compression waves; to smell you must react to certain molecules. Immortality without those would be a bit dull. |
| 5725 | An immortal mind couldn't work harmoniously with a mortal body [Lucretius] |
| Full Idea: It is crazy to couple a mortal object with an eternal and suppose that they can work in harmony and mutually interact. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.799) | |
| A reaction: An interesting thought, though not a terrible persuasive argument. A god would indeed be a bit restless if it were chained to a human being, but it would presumably knuckle down to the task if firmly instructed to do it by Zeus. |
| 5720 | Spirit is mortal [Lucretius] |
| Full Idea: Spirit is mortal. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.542) | |
| A reaction: This is asserted at an historical moment when immortality is beginning to grip everyone's imagination. |
| 5721 | The mind is very small smooth particles, which evaporate at death [Lucretius] |
| Full Idea: Since the substance of the mind is extraordinarily mobile, it must consist of particles exceptionally small and smooth and round, ..so that, when the spirit has escaped from the body, the outside of the limbs appears intact and there is no loss of weight. | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.201) | |
| A reaction: Lucretius is wonderfully attentive to interesting evidence. He goes on to compare it to the evaporation of perfume. The fine-grained connections of the brain are not far off what he is proposing. |
| 5723 | If spirit is immortal and enters us at birth, why don't we remember a previous existence? [Lucretius] |
| Full Idea: If the spirit is by nature immortal and is slipped into the body at birth, why do we retain no memory of an earlier existence, no impress of antecedent events? | |
| From: Lucretius (On the Nature of the Universe [c.60 BCE], III.670) | |
| A reaction: Plato took the view that we do recall previous existence, as seen in our innate ideas. This problem forced the Christian church into the uncomfortable claim that God creates the soul at conception, but that it then goes on to immortality. |