| 1821 | Sensations cannot be judged, because similar sensations have equal value, and different ones have nothing in common [Epicurus, by Diog. Laertius] |
| Full Idea: Sensation is out of reach of control, because one sensation cannot judge another which resembles itself, as they have equal value, and different sensations have different objects. | |
| From: report of Epicurus (fragments/reports [c.289 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 10.20 | |
| A reaction: Scepticism about the possibility of purely empirical knowledge; an interesting comment on the question of whether perceptions contain any intrinsic knowledge. |
| 20792 | Stoic perception is a presentation to which one voluntarily assents [Stoic school, by Stobaeus] |
| Full Idea: The Stoics did not make sense-perception consist in presentation alone but made its substance depend on assent; for perception is an assent to a perceptual presentation, the assent being voluntary. | |
| From: report of Stoic school (fragments/reports [c.200 BCE]) by John Stobaeus - Anthology 1.49.25 | |
| A reaction: [Stobaeus cites Porphyry's De Anima] Thus you only perceive a hallucination if you do not realise that it is false. This is more subjective than I would want to be. If you only think you perceive, but you are wrong, then I say you don't perceive. |
| 1883 | How can the intellect know if sensation is reliable if it doesn't directly see external objects? [Sext.Empiricus] |
| Full Idea: Just as you can't know if a portrait of Socrates is good without seeing the man, so when the intellect gazes on sensations but not the external objects it cannot know whether they are similar. | |
| From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.75) |
| 2295 | Why does pain make us sad? [Descartes] |
| Full Idea: Why should a certain sadness of spirit arise from a sensation of pain? | |
| From: René Descartes (Meditations [1641], §6.76) |
| 4831 | If the body is affected by an external object, the mind can't help believing that the object exists [Spinoza] |
| Full Idea: If the human body is affected in a manner which involves the nature of any external body, the human mind will regard the said external body as actually existing. | |
| From: Baruch de Spinoza (The Ethics [1675], II Pr 17) | |
| A reaction: This is like one of Hume's 'natural beliefs', and seems to me a powerful idea. One of the basic questions of epistemology is, apart from the question 'which beliefs can I justify?', also 'which beliefs can I never abandon?' Skip the scepticism? |
| 23639 | It is unclear whether a toothache is in the mind or in the tooth, but the word has a single meaning [Reid] |
| Full Idea: If it be made a question whether the toothache be in the mind that feels it, or in tooth that is affected, much might be said on both sides, while it is not observed that the word has two meanings. | |
| From: Thomas Reid (Essays on Intellectual Powers 2: Senses [1785], 18) | |
| A reaction: I'm glad Reid was struck by the weird phenomenon of the brain apparently 'projecting' a pain into a tooth. Presumably before the brain's role was known, people were unaware of this puzzle. There certainly are not two distinct experiences. |
| 2774 | Kant says the cognitive and sensory elements in experience can't be separated [Kant, by Dancy,J] |
| Full Idea: Kant maintains that it is impossible to draw a suitable distinction between the cognitive and sensory 'elements' in sensory experience. | |
| From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Jonathan Dancy - Intro to Contemporary Epistemology 8.4 |
| 22033 | Hegel tried to avoid Kant's dualism of neutral intuitions and imposed concepts [Hegel, by Pinkard] |
| Full Idea: Hegel tried to avoid the untenable Kantian dualism between concepts and intuitions, and the Kantian mechanism of the 'imposition' of concepts on sensibility entailed by that dualism (with intuition having neutral content). | |
| From: report of Georg W.F.Hegel (Phenomenology of Spirit [1807]) by Terry Pinkard - German Philosophy 1760-1860 09 | |
| A reaction: [Pinker is describing the opening of Phenomenology] In modern discussions this concerns the idea of The Given, which is wholly uninterpreted raw experience. Sellars and MacDowell. Kant seems to split an agent into two (Master/Slave). |
| 4163 | All perception is intellectual [Schopenhauer] |
| Full Idea: All perception is intellectual. | |
| From: Arthur Schopenhauer (The World as Will and Idea [1819], I 004) | |
| A reaction: Even in slugs? I suspect that this is a tautology. Schopenhauer will only allow my vision or hearing to become 'perception' when an intellectual element enters into it. |
| 2878 | We see an approximation of a tree, not the full detail [Nietzsche] |
| Full Idea: We do not see a tree exactly and entire with regard to its leaves, branches, colour and shape; it is so much easier for us to see an approximation of a tree. | |
| From: Friedrich Nietzsche (Beyond Good and Evil [1886], §192) |
| 7156 | Sense perceptions contain values (useful, so pleasant) [Nietzsche] |
| Full Idea: All sensory perceptions are entirely suffused with value judgements (useful or harmful - consequently pleasant or unpleasant). | |
| From: Friedrich Nietzsche (Writings from Late Notebooks [1887], 02[95]) | |
| A reaction: This seems like a wonderful anticipation of modern neuroscience findings about emotion. It is a nice challenge to Hume's 'impressions' and Russell's 'logical atoms'. But knowledge is power, and we can strip off the values from the perceptions. |
| 7181 | Pain shows the value of the damage, not what has been damaged [Nietzsche] |
| Full Idea: Intellectuality of pain: pain does not indicate what is momentarily damaged but what value the damage has with regard to the individual as a whole. | |
| From: Friedrich Nietzsche (Writings from Late Notebooks [1887], 07[48]) | |
| A reaction: An interesting claim, but rather hard to substantiate. Boiling water on the back of a hand might be very painful, but not of huge consequence in terms of damage. The palm of the hand is much more important to us than the back. |
| 7129 | Perception is unconscious, and we are only conscious of processed perceptions [Nietzsche] |
| Full Idea: Sense-perception happens without our awareness: whatever we become conscious of is a perception that has already been processed. | |
| From: Friedrich Nietzsche (Writings from Late Notebooks [1887], 34[30]) | |
| A reaction: This seems to me wonderfully perceptive for its date, and a crucial truth, because we have the delusion that we are our consciousness, whereas that is only a tiny part of what we are. |
| 6098 | Perception goes straight to the fact, and not through the proposition [Russell] |
| Full Idea: I am inclined to think that perception, as opposed to belief, does go straight to the fact and not through the proposition. | |
| From: Bertrand Russell (The Philosophy of Logical Atomism [1918], §IV.4) | |
| A reaction: There seems to be a question of an intermediate stage, which is the formulation of concepts. Is full 'perception' (backed by attention and intellect) laden with concepts, which point to facts? Where are the facts in sensation without recognition? |
| 20749 | Perceived objects always appear in a context [Heidegger] |
| Full Idea: The perceptual 'something' is always in the middle of something else, it always forms part of a 'field'. | |
| From: Martin Heidegger (Being and Time [1927], p.4), quoted by Kevin Aho - Existentialism: an introduction 3 'Perceptual' | |
| A reaction: Sounds like our knowledge of electrons. Nice point. Standard analytic discussions of perceiving a glass always treat it in isolation, when it is on an expensive table near a brandy bottle. Or near a hammer. |
| 18278 | Kant showed that our perceptions are partly constructed from our concepts [Reichenbach] |
| Full Idea: It was Kant's great discovery that the object of knowledge is not simply given but constructed, and that it contains conceptual elements not contained in pure perception. | |
| From: Hans Reichenbach (The Theory of Relativity and A Priori Knowledge [1965], p.49), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap |
| 20750 | The mind does not unite perceptions, because they flow into one another [Merleau-Ponty] |
| Full Idea: I do not have one perception, then another, and between them a link brought about by the mind. Rather, each perspective merges into the other [against a unified background]. | |
| From: Maurice Merleau-Ponty (Phenomenology of Perception [1945], p.329-30), quoted by Kevin Aho - Existentialism: an introduction 3 'Perceptual' | |
| A reaction: I take this to be another piece of evidence pointing to realism as the best explanation of experience. A problem for Descartes is what unites the sequence of thoughts. |
| 22449 | When we say 'is red' we don't mean 'seems red to most people' [Foot] |
| Full Idea: One might think that 'is red' means the same as 'seems red to most people', forgetting that when asked if an object is red we look at it to see if it is red, and not in order to estimate the reaction that others will have to it. | |
| From: Philippa Foot (Moral Relativism [1979], p.23) | |
| A reaction: True, but we are conscious of our own reliability as observers (e.g. if colourblind, or with poor hearing or eyesight). I don't take my glasses off, have a look, and pronounce that the object is blurred. Ordinary language philosophy in action. |
| 3482 | Perception is a function of expectation [Searle] |
| Full Idea: Psychologists have a lot of evidence to show that perception is a function of expectation. | |
| From: John Searle (The Rediscovery of the Mind [1992], Ch. 6.I.7) |
| 4049 | The way in which colour experiences are evoked is physically odd and unpredictable [Goldman] |
| Full Idea: A unique yellow experience may be evoked with monochrome light of 580nm, or a mixture of 540nm and 670nm. ..Our interpretation of colour experience is a highly idiosyncratic artefact of our visual system. | |
| From: Alvin I. Goldman (Phil Applications of Cognitive Science [1993], p.117) | |
| A reaction: This confirms what I have always thought - that colour (as qualia) is strictly a feature of minds, not of the world. |
| 19092 | There is no pure Given, but it is cultured, rather than entirely relative [McDowell, by Macbeth] |
| Full Idea: McDowell argues that the Myth of the Given shows not that there is no content to a concept that is not a matter of its inferential relations to other concepts but only that awareness of the sort that we enjoy ...is acquired in the course of acculturation. | |
| From: report of John McDowell (Mind and World [1994]) by Danielle Macbeth - Pragmatism and Objective Truth p.185 | |
| A reaction: The first view is of Wilfred Sellars, who derives pragmatic relativism from his rejection of the Myth. This idea is helpful is seeing why McDowell has a good proposal. As I look out of my window, my immediate experience seems 'cultured'. |
| 2718 | Perception is first simple, then objectual (with concepts) and then propositional [Audi,R] |
| Full Idea: Simple perceiving gives rise to objectual perceiving (attaching concepts to the object), which gives rise to propositional perceiving. | |
| From: Robert Audi (Epistemology: contemporary introduction [1998], I p.23) |
| 4910 | Sense organs don't discriminate; they reduce various inputs to the same electrical pulses [Carter,R] |
| Full Idea: Despite their variety, each sense organ translates its stimulus into electrical pulses; rather than discriminating one type of input from another, the sense organs actually make them more alike. | |
| From: Rita Carter (Mapping the Mind [1998], p.174) | |
| A reaction: An illuminating observation, which modern 'naïve realists' should bear in mind. Secondary qualities are entirely unrelated to the nature of the input, and are merely 'what the brain decides to make of it'. Discrimination is in our neurons. |
| 4911 | The recognition sequence is: classify, name, locate, associate, feel [Carter,R, by PG] |
| Full Idea: The sequence of events in the brain for perceptual recognition is first identifying a rough class for the object, then a name, then a location, then some associations, and finally an emotion. | |
| From: report of Rita Carter (Mapping the Mind [1998], p.181) by PG - Db (ideas) | |
| A reaction: This seems to be one of those places where neuro-science trumps philosophy. You can't argue with empirical research, so philosophical theories had better adapt themselves to this sequence. The big modern discovery is the place of emotion in recognition. |
| 9124 | We are unable to perceive a nose (on the back of a mask) as concave [Sorensen] |
| Full Idea: The human perceptual system appears unable to represent a nose as concave rather than convex. If you look at the concave side of a mask, you see the features as convex. | |
| From: Roy Sorensen (Vagueness and Contradiction [2001], 4.3) | |
| A reaction: I don't think that is quite true. You wouldn't put a mask on if you thought it was convex. It is usually when seen at a distance with strong cross-lighting that the effect emerges. Nevertheless, it is an important point. |
| 17979 | Research shows perceptual discrimination is sharper at category boundaries [Murphy] |
| Full Idea: Goldstone's research has shown how learning concepts can change perceptual units. For example, perceptual discrimination is heightened along category boundaries. | |
| From: Gregory L. Murphy (The Big Book of Concepts [2004], Ch.13) | |
| A reaction: [Goldstone 1994, 2000] This is just the sort of research which throws a spanner into the simplistic a priori thinking of many philosophers. |