Combining Philosophers

Ideas for Ian Dunt, Alonzo Church and Gottfried Leibniz

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21 ideas

12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
21253 Descartes needs to demonstrate how other people can attain his clear and distinct conceptions [Leibniz]
     Full Idea: It is not sufficient for Descartes to claim that he perceives something in himself clearly and distinctly, for this is to not complete the demonstration, unless he shows the method through which others can attain the same experience.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], App X)
     A reaction: For the simplest rational insight this seems a rather tough requirement. If you say A>B, and B>C, so A>C, then once you have grasped the concept of 'greater than' I'm not sure there is a further possible demonstration.
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / a. Innate knowledge
12933 Arithmetic and geometry are implicitly innate, awaiting revelation [Leibniz]
     Full Idea: I would name the propositions of arithmetic and geometry as innate. ...The actual knowledge of them is not innate. What is innate is what might be called the implicit knowledge of them, as the veins of marble outline a shape for the sculptor.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 1.01)
     A reaction: This seems to walk straight into the empiricist guns. The marble example shows the problem, because the 'veins' will hardly outline David in the block. Locke's challenge is to show that merely 'implicit' ideas have demonstrable reality.
12991 Children learn language fast, with little instruction and few definitions [Leibniz]
     Full Idea: I have sometimes been amazed that children can learn languages so early, ...considering how little trouble is taken to instruct children in their native tongue, and how little thought adults give to getting sharp definitions.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.10)
     A reaction: A striking anticipation of the key observation on which Chomsky built his theories, from a philosopher who was equally concerned to defend innate ideas and innate knowledge.
12929 All of our thoughts come from within the soul, and not from the senses [Leibniz]
     Full Idea: I always accepted the innate idea of God, but my new system says all the thoughts and actions of the soul come from its own depths and could not be given to it by the senses.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 1.01)
     A reaction: It is hard to adjudicate on this one. The counterexamples would be associations. I see a face in the crowd and think of my friend. But Leibniz could be right even about that. Who cares? Externalism is designed to bypass this problem.
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / c. Tabula rasa
12940 What is left of the 'blank page' if you remove the ideas? [Leibniz]
     Full Idea: Those who hold forth about the 'blank page' cannot say what is left of it once the ideas have been taken away.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.01)
     A reaction: This is a decisive criticism of the total tabula rasa idea, but empiricists responded by developing associationism - that what remains is principles of association for incoming experience. Brain mechanisms, we might say.
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
9344 Mathematical analysis ends in primitive principles, which cannot be and need not be demonstrated [Leibniz]
     Full Idea: At the end of the analytical method in mathematics there are simple ideas of which no definition can be given. Moreover there are axioms and postulates, in short, primitive principles, which cannot be demonstrated and do not need demonstration.
     From: Gottfried Leibniz (Monadology [1716], §35)
     A reaction: My view is that we do not know such principles when we apprehend them in isolation. I would call them 'intuitions'. They only ascend to the status of knowledge when the mathematics is extended and derived from them, and found to work.
9155 An a priori proof is independent of experience [Leibniz]
     Full Idea: An a priori proof is a proof independent of experience.
     From: Gottfried Leibniz (Primary Truths [1686])
     A reaction: Burge says Leibniz gave the first modern account of a priori knowledge. There may be no explicit reference to experience involved, but it would beg many questions to deny that implicit experience may be at the root of the proof.
12. Knowledge Sources / B. Perception / 1. Perception
19419 Not all of perception is accompanied by consciousness [Leibniz]
     Full Idea: I do not think that the Cartesians have ever proved or can prove that every perception is accompanied by consciousness.
     From: Gottfried Leibniz (Principle of Life and Plastic Natures [1705], p.195)
     A reaction: This idea is very important in Leibniz, because non-conscious or barely conscious thoughts and perceptions explain a huge amount about behaviour, reality and morality.
19353 'Perception' is basic internal representation, and 'apperception' is reflective knowledge of perception [Leibniz]
     Full Idea: We distinguish between 'perception', the internal state of the monad representing external things, and 'apperception', which is consciousness, or the reflective knowledge of this internal state, not given to all souls, nor at all times to a given soul.
     From: Gottfried Leibniz (Principles of Nature and Grace based on Reason [1714], §4)
     A reaction: The word 'apperception' is standard in Kant. I find it surprising that modern analytic philosophers don't seem to use it when they write about perception. It strikes me as useful, but maybe specialists have a reason for avoiding it.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / d. Secondary qualities
19430 We know objects by perceptions, but their qualities don't reveal what it is we are perceiving [Leibniz]
     Full Idea: We use the external senses ...to make us know their particular objects ...but they do not make us know what those sensible qualities are ...whether red is small revolving globules causing light, heat a whirling of dust, or sound is waves in air.
     From: Gottfried Leibniz (Letters to Queen Charlotte [1702], 1702)
     A reaction: These seems to be exactly the concept of secondary qualities which Locke was promoting. They are unreliable information about the objects we perceive. Primary qualities are reliable information. I like that distinction.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / e. Primary/secondary critique
12721 Light, heat and colour are apparent qualities, and so are motion, figure and extension [Leibniz]
     Full Idea: Concerning bodies I can demonstrate that not merely light, heat, color, and similar qualities are apparent but also motion, figure, and extension.
     From: Gottfried Leibniz (De modo distinguendi phaenomena [1685], A6.4.1504), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 4
     A reaction: Leibniz is not consistent on this. Here he is flirting with idealism, but he often backs away from that. In Discourse §12 he makes secondary qualities certainly subjective, and primary qualities possibly so. He admits the primaries contain eternal truths.
19358 Colour and pain must express the nature of their stimuli, without exact resemblance [Leibniz]
     Full Idea: Ideas such as those of colour and pain are not arbitrary. ...That is not God's way ...I would say there is a resemblance of a kind, not a perfect one, but a resemblance in which one thing expresses another through some orderly relationship between them.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.08)
     A reaction: The main point of Locke's idea of 'secondary' qualities is that (unlike the 'primary' ones) they bear no resemblance to their stimuli. It's not much of an argument from Leibniz, to say that is not God's way, but he has a vast system to support his claim.
12. Knowledge Sources / B. Perception / 3. Representation
12948 A pain doesn't resemble the movement of a pin, but it resembles the bodily movement pins cause [Leibniz]
     Full Idea: It is true that pain does not resemble the movement of a pin; but it might thoroughly resemble the motions which the pin causes in our body, and it might resemble them in the soul; and I have not the least doubt that it does.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.08)
     A reaction: He may not have the least doubt, but the rest of us do, I should think. Try as I will, I cannot see any resemblance between pain and a motion. What feeling does a pendulum resemble?
12. Knowledge Sources / B. Perception / 6. Inference in Perception
13005 Truth arises among sensations from grounding reasons and from regularities [Leibniz]
     Full Idea: The truth of sensible things is established by the links amongst them; these depend upon intellectual truths, grounded in reason, and upon observations of regularities among sensible things themselves, even when the reasons are not apparent.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 4.11)
     A reaction: It's not clear why regularities would establish truths, given that most hallucinations have regularities in them. I'm thinking that Leibniz is not sufficiently rationalist here, and that it is the rational coherence of experience which validates it.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
4302 You may experience a universal truth, but only reason can tell you that it is always true [Leibniz]
     Full Idea: However often one experiences instances of a universal truth, one could never know inductively that it would always hold unless one knew through reason that it was necessary.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 1.01)
     A reaction: The problem, though, is that as soon as we go beyond experience we are not very reliable, and are liable to arrogance, error and lack of imagination.
12947 We only believe in sensible things when reason helps the senses [Leibniz]
     Full Idea: The senses could not convince us of the existence of sensible things without help from reason.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.07)
     A reaction: This nicely pinpoints the big difficulty which keeps besetting orthodox empiricism. I've been educated as an empiricist, but I prefer Leibniz to Berkeley or Hume, and even to the more sensible Locke.
2110 We all expect the sun to rise tomorrow by experience, but astronomers expect it by reason [Leibniz]
     Full Idea: When we expect it to be day tomorrow, we all behave as empiricists, because until now it has always happened thus. The astronomer alone knows this by reason.
     From: Gottfried Leibniz (Monadology [1716], §28)
12930 The senses are confused, and necessities come from distinct intellectual ideas [Leibniz]
     Full Idea: Intellectual ideas, from which necessary truths arise, do not come from the senses. ...The ideas that come from the senses are confused; and so too, at least in part, are the truths which depend on them, whereas intellectual ideas are distinct.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 1.01)
     A reaction: One might compare Descartes' example of the chiliagon, which is only grasped clearly by the intellect. However, the problem of vagueness seems to intrude as much into intellectual ideas as it does into the senses. He was a mathematician...
12. Knowledge Sources / D. Empiricism / 1. Empiricism
19431 There is nothing in the understanding but experiences, plus the understanding itself, and the understander [Leibniz]
     Full Idea: It can be said that there is nothing in the understanding which does not come from the senses, except the understanding itself, or that which understands.
     From: Gottfried Leibniz (Letters to Queen Charlotte [1702], 1702)
     A reaction: Given that Leibniz is labelled as a 'rationalist', this is awfully close to empiricism. Not Locke's 'tabula rasa' perhaps, but Hume's experiences plus associations. Leibniz has a much loftier notion of understanding and reason than Hume does.
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
5024 Knowledge doesn't just come from the senses; we know the self, substance, identity, being etc. [Leibniz]
     Full Idea: It is always false to say that all our notions come from the so-called external senses, for the notion I have of myself and of my thoughts, and consequently of being, substance, action, identity, and many others, come from an internal experience.
     From: Gottfried Leibniz (Discourse on Metaphysics [1686], §27)
     A reaction: Of course, an empiricist like Hume would not deny this, as he bases his views on 'experience' (including anger, for example), not just 'sense experience'. But Hume, famously, said he has no experience of a Self, so can't get started on Leibniz's journey.
13001 Our sensation of green is a confused idea, like objects blurred by movement [Leibniz]
     Full Idea: The sensory idea of green (made of blue and yellow) is a confused idea, like the swift rotation of a cog-wheel which makes us perceive an artificial transparency, and we are not able to discern the cause, the idea of the teeth on the wheel.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 4.06)
     A reaction: This is one of Leibniz's less well-known objections to empiricism. He always says that intellectual ideas are capable of a clarity which is never found in sensory experience.