| 1919 | You don't need to learn what you know, and how do you seek for what you don't know? [Plato] |
| Full Idea: You could argue that a man cannot discover what he does know or what he doesn't. The first needs no discovery, and how do you begin looking for the second? | |
| From: Plato (Meno [c.385 BCE], 80e) |
| 1762 | When someone denied motion, Diogenes got up and walked away [Diogenes of Sin., by Diog. Laertius] |
| Full Idea: Diogenes replied to one who asserted that there was no such thing as motion by getting up and walking away. | |
| From: report of Diogenes (Sin) (reports [c.360 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 06.Di.6 |
| 6592 | Academics said that Pyrrhonians were guilty of 'negative dogmatism' [Pyrrho, by Fogelin] |
| Full Idea: The ancient Academic sceptics charged the Pyrrhonian sceptics with 'negative dogmatism' when they claimed that a certain kind of knowledge is impossible. | |
| From: report of Pyrrho (reports [c.325 BCE]) by Robert Fogelin - Walking the Tightrope of Reason Ch.4 | |
| A reaction: It is this kind of point which should push us towards some sort of rationalism, because certain a priori 'dogmas' seem to be indispensable to get any sort of discussion off the ground. The only safe person is Cratylus (see Idea 578). |
| 20794 | How can sceptics show there is no criterion? Weak without, contradiction with [Sext.Empiricus] |
| Full Idea: The dogmatists ask how the sceptic can show there is no criterion. If without a criterion, he is untrustworthy; with a criterion he is turned upside down. He says there is no criterion, but accepts a criterion to establish this. | |
| From: Sextus Empiricus (Against the Mathematicians [c.180], 440) | |
| A reaction: This is also the classic difficulty for foundationalist views of knowledge. Is the foundation justified, or not? |
| 3064 | When sceptics say that nothing is definable, or all arguments have an opposite, they are being dogmatic [Diog. Laertius] |
| Full Idea: When sceptics say that they define nothing, and that every argument has an opposite argument, they here give a positive definition, and assert a positive dogma. | |
| From: Diogenes Laertius (Lives of Eminent Philosophers [c.250], 9.11.11) |
| 3604 | When rebuilding a house, one needs alternative lodgings [Descartes] |
| Full Idea: Before beginning to rebuild the house in which one lives…. one must also provide oneself with some other accommodation in which to be lodge conveniently while the work is going on. | |
| From: René Descartes (A Discourse on Method [1637], §3.22) |
| 2294 | I can only sense an object if it is present, and can't fail to sense it when it is [Descartes] |
| Full Idea: Perceptions come upon me without my consent, to the extent that, wish as I may, I could not sense any object unless it was present to a sense organ, nor could I fail to sense it when it was present. | |
| From: René Descartes (Meditations [1641], §6.75) |
| 6488 | Locke has no patience with scepticism [Locke, by Robinson,H] |
| Full Idea: Locke has no patience with scepticism. | |
| From: report of John Locke (Essay Conc Human Understanding (2nd Ed) [1694]) by Howard Robinson - Perception 1.4 | |
| A reaction: Neither did Hume, and Aristotle laughs at extreme scepticism, and it never really bothers Plato. It could be argued that Descartes just regards it as a strategy for getting at foundations, rather than being something that kept him awake at night. |
| 19392 | I don't recommend universal doubt; we constantly seek reasons for things which are indubitable [Leibniz] |
| Full Idea: I do not think it necessary to recommend to people universal doubt ...in fact, we are constantly seeking reasons for thoughts about which there is no doubt at all. | |
| From: Gottfried Leibniz (Precepts for Advancing Science and Arts [1680], p.34) | |
| A reaction: Such confidence is, of course, asking for trouble. I prefer Peirce's fallibilism - that robust realism is the most coherent view, and the only one worth pursuing and relying on, but you never know.... |
| 2240 | It is a very extravagant aim of the sceptics to destroy reason and argument by means of reason and argument [Hume] |
| Full Idea: It may seem a very extravagant attempt of the sceptics to destroy reason by argument and ratiocination; yet is this the grand scope of all their enquiries and disputes. | |
| From: David Hume (Enquiry Conc Human Understanding [1748], XII.II.124) |
| 2241 | The main objection to scepticism is that no good can come of it [Hume] |
| Full Idea: The chief and most confounding objection to excessive scepticism is that no durable good can ever result from it. | |
| From: David Hume (Enquiry Conc Human Understanding [1748], XII.II.128) |
| 5592 | Scepticism is the euthanasia of pure reason [Kant] |
| Full Idea: Reason is tempted to surrender itself to a sceptical hopelessness, which might also be called the euthanasia of pure reason. | |
| From: Immanuel Kant (Critique of Pure Reason [1781], B434/A407) | |
| A reaction: Colin McGinn's 'mysterian' pessimism about the mind-body problem comes to mind! |
| 5595 | Scepticism is absurd in maths, where there are no hidden false assertions [Kant] |
| Full Idea: The sceptical method would be absurd in mathematics, because nowhere in mathematics do false assertions disguise themselves and make themselves invisible. | |
| From: Immanuel Kant (Critique of Pure Reason [1781], B452/A424) | |
| A reaction: An interesting observation. The implication I take here is that scepticism in the realm of sensation is justified, precisely because errors and illusion do occur. |
| 22780 | It is a rejection of intellectual dignity to say that we cannot know the truth [Hegel] |
| Full Idea: The assertion that human beings cannot know the truth, but have to do only with appearances …deprives the spirit of intellectual dignity. | |
| From: Georg W.F.Hegel (Elements of the Philosophy of Right [1821], 132) | |
| A reaction: It is a relief to find Hegel making this assertion. His later followers seem to have slid into an extreme cultural relativism. I'm not sure that 'intellectual dignity' is a very secure foundation for his claim. |
| 6945 | Once doubt ceases, there is no point in continuing to argue [Peirce] |
| Full Idea: Some people seem to love to argue a point after all the world is fully convinced of it. But no further advance can be made. When doubt ceases, mental action on the subject comes to an end; and, if it did go on, it would be without purpose. | |
| From: Charles Sanders Peirce (The Fixation of Belief [1877], p.11) | |
| A reaction: This is the way Peirce's pragmatism, which deals with how real thinking actually works (rather than abstract logic), deals with scepticism. However, there is a borderline where almost everyone is satisfied, but the very wise person remains sceptical. |
| 22206 | Natural science has become great by just ignoring ancient scepticism [Husserl] |
| Full Idea: Natural science has grown to greatness by pushing ruthlessly aside the rank growth of ancient skepticism and renouncing the attempt to conquer it. | |
| From: Edmund Husserl (Ideas: intro to pure phenomenology [1913], I.2.026) | |
| A reaction: This may be because scepticism is boring, or it may be because science 'brackets' scepticism, leaving philosophers to worry about it. |
| 21578 | Global scepticism is irrefutable, but can't replace our other beliefs, and just makes us hesitate [Russell] |
| Full Idea: Universal scepticism, though logically irrefutable, is practically barren; it can only, therefore, give a certain flavour of hesitancy to our beliefs, and cannot be used to substitute other beliefs for them. | |
| From: Bertrand Russell (Our Knowledge of the External World [1914], 3) | |
| A reaction: Spot on. There is no positive evidence for scepticism, so must just register it as the faintest of possibilities, like the existence of secretive fairies. |
| 22163 | The scandal of philosophy is expecting to prove reality when the prover's Being is vague [Heidegger] |
| Full Idea: The 'scandal of philosophy' is not that this proof [of external things] has yet to be given, but that such proofs are expected and attempted again and again. ...The kind of Being of the entity which does the proving has not been made definite enough. | |
| From: Martin Heidegger (Being and Time [1927], I.6.43a) | |
| A reaction: The 'scandal' was a remark of Kant's. Presumably Heidegger's exploration of Dasein aims to establish the Being of the prover sufficiently to solve this problem (via phenomenology). |
| 3596 | Total doubt can't even get started [Wittgenstein, by Williams,M] |
| Full Idea: Wittgenstein remarked that if you tried to doubt everything, you would not get as far as doubting anything. | |
| From: report of Ludwig Wittgenstein (On Certainty [1951]) by Michael Williams - Problems of Knowledge Ch.14 |
| 4160 | One can mistrust one's own senses, but not one's own beliefs [Wittgenstein] |
| Full Idea: One can mistrust one's own senses, but not one's own beliefs. | |
| From: Ludwig Wittgenstein (Philosophical Investigations [1952], II.x) | |
| A reaction: This seems right, because we don't choose our beliefs. We don't even choose whether to believe a sensation - we just focus harder until belief does or doesn't occur. |
| 8805 | Skepticism is false because our utterances agree, because they are caused by the same objects [Davidson] |
| Full Idea: What stands in the way of global skepticism of the senses is the fact that we must take the objects of a belief to be the causes of that belief. And our utterances mean the same thing because belief in their truth is caused by the same objects. | |
| From: Donald Davidson (Coherence Theory of Truth and Knowledge [1983], p.161) | |
| A reaction: This is hardly a knock-down argument against scepticism, but it builds a nice picture. The second half extends the Private Language Argument (e.g. Idea 4158). But I still have non-existent conversations about non-existent things in my dreams. |
| 2566 | You can't debate about whether to have higher standards for the application of words [Rorty] |
| Full Idea: The decision about whether to have higher than usual standards for the application of words like "true" or "good" or "red" is, as far as I can see, not a debatable issue. | |
| From: Richard Rorty (Philosophy and the Mirror of Nature [1980], 6.6) |
| 3252 | Scepticism is based on ideas which scepticism makes impossible [Nagel] |
| Full Idea: The sceptic reaches scepticism through thoughts that scepticism makes unthinkable. | |
| From: Thomas Nagel (The View from Nowhere [1986], V.6) |
| 2743 | What is the point of arguing against knowledge, if being right undermines your own argument? [Dancy,J] |
| Full Idea: What is the point of arguing that justified belief is impossible, for if you were right there could be no reasons for your conclusion? | |
| From: Jonathan Dancy (Intro to Contemporary Epistemology [1985], 1.3) |
| 3880 | Logical positivism avoids scepticism, by closing the gap between evidence and conclusion [Scruton] |
| Full Idea: If the evidence for p is q, and that is the only evidence there is or can be, then 'p' means q. Hence there is no gap between evidence and conclusion, and the sceptical problem does not arise. | |
| From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 3.2) |
| 19559 | Contextualists slightly concede scepticism, but only in extremely strict contexts [Cohen,S] |
| Full Idea: Contextualism concedes that there is some truth to skepticism, but contains the damage by holding that skeptical claims are true only relative to atypically strict contexts. | |
| From: Stewart Cohen (Contextualism Defended (and reply) [2005], 1) | |
| A reaction: My attitude to scepticism is that everything we ever affirm should have a footnote saying '...but you never know...', and it should then be ignored. In the strictest context everything is doubted simultaneously (including language), and that is paralysis. |
| 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. |
| 3761 | Modern arguments against the sceptic are epistemological and semantic externalism, and the focus on relevance [Bernecker/Dretske] |
| Full Idea: In modern epistemology the three strategies to rebut the sceptic are 1) epistemological externalism, 2) the 'relevant alternative account of knowledge' (that scepticism is too extreme to be relevant), and 3) semantic externalism. | |
| From: Bernecker / Dretske (Knowledge:Readings in Cont.Epist [2000], Pt.IV Int) |
| 6590 | Scepticism deals in remote possibilities that are ineliminable and set the standard very high [Fogelin] |
| Full Idea: Sceptical scenarios deal in wildly remote defeating possibilities, so that the level of scrutiny becomes unrestrictedly high, and they also usually deal with defeators that are in principle ineliminable. | |
| From: Robert Fogelin (Walking the Tightrope of Reason [2003], Ch.4) | |
| A reaction: The question of how high we 'set the bar' seems to me central to epistemology. There is clearly an element of social negotiation involved, centring on what is appropriate. If, though, scepticism is 'ineliminable', we must face up to that. |
| 19507 | Radical scepticism is merely raised, and is not a response to worrying evidence [Pritchard,D] |
| Full Idea: Crucially, radical sceptical error-possibilities are never epistemically motivated, but are instead merely raised. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§5) | |
| A reaction: In 'The Matrix' someone sees a glitch in the software (a cat crossing a passageway), and that would have to be taken seriously. Otherwise it is a nice strategy to ask why the sceptic is raising this bizzare possibility, without evidence. |