22 ideas
11197 | The definitions expressing identity are used to sort things [Aquinas] |
Full Idea: What sorts things into their proper genus and species are the definitions that express what they are. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92) | |
A reaction: This is straight from Aristotle, though Aristotle's view is a little more complex, I think. If the definitions 'express what they are', then definitions seem to specify the essence. |
13070 | If definitions must be general, and general terms can't individuate, then Socrates can't be defined [Aquinas, by Cover/O'Leary-Hawthorne] |
Full Idea: Socrates has no definition if definitions by their nature must be in purely general terms, and if no purely general terms can succeed in uniquely singling out this signated matter. | |
From: report of Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], 23) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 1.1.2 | |
A reaction: There seem to be two models. That general terms actually individuate the matter of Socrates, or that they cross-reference to (so to speak) define Socrates 'by elimination', as the only individual that fits. But the latter is a poor definition. |
11195 | If affirmative propositions express being, we affirm about what is absent [Aquinas] |
Full Idea: If being is what makes propositions true, then anything we can express in an affirmative proposition, however unreal, is said to be; so lacks and absences are, since we say that absences are opposed to presences, and blindness exists in an eye. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92) | |
A reaction: See Idea 11194 for the alternative Aristotelian approach to being, according to categories. Do absences and lacks have real essences, or causal properties? The absence of the sentry may cause the loss of the city. |
11201 | Properties have an incomplete essence, with definitions referring to their subject [Aquinas] |
Full Idea: Incidental properties have an incomplete essence, and need to refer in their definitions to their subject, lying outside their own genus. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.93) | |
A reaction: These are 'incidental' properties, but it is a nice question whether properties have essences. Presumably they must have if they are universals, or platonic Forms. The notion of being 'strong' can be defined without specific examples. |
11205 | If the form of 'human' contains 'many', Socrates isn't human; if it contains 'one', Socrates is Plato [Aquinas] |
Full Idea: If (in the Platonic view) manyness was contained in humanness it could never be one as it is in Socrates, and if oneness was part of its definition then Socrates would be Plato and the nature couldn't be realised more than once. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.100) | |
A reaction: I suppose the reply is that since we are trying to explain one-over-many, then this unusual combination of both manyness and oneness is precisely what distinguishes forms from other ideas. |
13090 | The principle of diversity for corporeal substances is their matter [Aquinas, by Cover/O'Leary-Hawthorne] |
Full Idea: In the view of Aquinas, while substantial form is the ultimate ground of identity and difference of angels, it is matter that provides a principle of diversity in the case of corporeal substances. | |
From: report of Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 5.2.3 | |
A reaction: This is at least as good a proposal as their apatial location. There is more chance of reidentifying matter than of precisely reidentifying a spatial location. Two indistinguishable spheres remain the classic problem case (of Max Black, Idea 10195) |
16678 | Without magnitude a thing would retain its parts, but they would have no location [Buridan] |
Full Idea: If magnitude were removed from matter by divine power, it would still have parts distinct from one another, but they would not be positioned either outside one another or inside one another, because position would be removed. | |
From: Jean Buridan (Questions on Aristotle's Physics [1346], I.8 f. 11va), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 14.4 | |
A reaction: This shows why Quantity is such an important category for scholastic philosopher. |
11202 | It is by having essence that things exist [Aquinas] |
Full Idea: It is by having essence that things exist. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.94) | |
A reaction: Compare Idea 11199, which gives a fuller picture. This idea seems to suggest essence as the cause of existence, which sounds wrong. Perhaps essence is a necessary condition of existence, but it is necessary that nothing indeterminate can exist? |
11203 | Specific individual essence is defined by material, and generic essence is defined by form [Aquinas] |
Full Idea: Specific essence differs from generic essence by being demarcated: individuals are demarcated within species by dimensionally defined material, but species within genus by a defining differentiation taken from the form. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.95) | |
A reaction: It clearly won't be enough to define an individual just to define its material and its shape. The material might also be essential to the genus, as when defining fire. Probably not very helpful. |
11200 | The definition of a physical object must include the material as well as the form [Aquinas] |
Full Idea: Form alone cannot be a composite substance's essence. For a thing's essence is expressed by its definition, and unless the definition of a physical substance included both form and material, the definition wouldn't differ from mathematical objects. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.93) | |
A reaction: This is the sort of thoroughly sensible remark that you only get from the greatest philosophers. Minor philosophers fall in love with things like forms, and then try to use them to explain everything. |
23647 | Objects have an essential constitution, producing its qualities, which we are too ignorant to define [Reid] |
Full Idea: Individuals and objects have a real essence, or constitution of nature, from which all their qualities flow: but this essence our faculties do not comprehend. They are therefore incapable of definition. | |
From: Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], 1) | |
A reaction: Aha - he's one of us! I prefer the phrase 'essential nature' of an object, which is understood, I think, by everyone. I especially like the last bit, directed at those who mistakenly think that Aristotle identified the essence with the definition. |
11196 | Essence is something in common between the natures which sort things into categories [Aquinas] |
Full Idea: Since being as belonging to a category expresses the 'isness' of things, and belongs to all ten Aristotelian categories, essence must be something all the natures that sort different beings into genera and species have in common. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92) | |
A reaction: I like this because it is the essence which does the sorting, not the sorting which defines the essence (which seems to me to be a deep and widespread confusion). |
11208 | A simple substance is its own essence [Aquinas] |
Full Idea: A simple substance is its own essence. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.103) | |
A reaction: Aquinas takes complex substances to have their essences in various ways, but this thought is the basis of all essence. Presumably the Greek word 'ousia' names the key ingredient. |
16793 | A thing is (less properly) the same over time if each part is succeeded by another [Buridan] |
Full Idea: Less properly, one thing is said to be numerically the same as another according to the continuity of distinct parts, one in succession after another. In this way the Seine is said to be the same river after a thousand years. | |
From: Jean Buridan (Questions on Aristotle's Physics [1346], I.10, f. 13vb), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 29.3 | |
A reaction: This is a rather good solution to the difficulty of the looser non-transitive notion of a thing being 'the same'. The Ship of Theseus endures (in the simple case) as long as you remember to replace each departing plank. Must some parts be originals? |
11958 | Impossibilites are easily conceived in mathematics and geometry [Reid, by Molnar] |
Full Idea: Reid pointed out how easily conceivable mathematical and geometric impossibilities are. | |
From: report of Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], IV.III) by George Molnar - Powers 11.3 | |
A reaction: The defence would be that you have to really really conceive them, and the only way the impossible can be conceived is by blurring it at the crucial point, or by claiming to conceive more than you actually can |
16577 | Induction is not demonstration, because not all of the instances can be observed [Buridan] |
Full Idea: Inductions are not demonstrations, because they do not conclude on account of their form, since it is not possible to make an induction from all cases. | |
From: Jean Buridan (Questions on Aristotle's Physics [1346], I.15 f. 18vb), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 02.3 | |
A reaction: Thus showing that demonstration really is meant to be as conclusive as a mathematical proof, and that Aristotle seems to think such a thing is possible in physical science. |
16576 | Science is based on induction, for general truths about fire, rhubarb and magnets [Buridan] |
Full Idea: Induction should be regarded as a principle of natural science. For otherwise you could not prove that every fire is hot, that all rhubarb is purgative of bile, that every magnet attracts iron. | |
From: Jean Buridan (Questions on Aristotle's Physics [1346], I.15 f. 18vb), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 02.3 | |
A reaction: He is basing this on Aristotle, and refers to 'Physics' 190a33-b11. |
11198 | Definition of essence makes things understandable [Aquinas] |
Full Idea: It is definition of essence that makes things understandable. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92) | |
A reaction: The aim of philosophy is understanding, which is achieved by successful explanation. I totally agree with this Aristotelian view, so neatly summarised by Aquinas. |
23646 | Reference is by name, or a term-plus-circumstance, or ostensively, or by description [Reid] |
Full Idea: An individual is expressed by a proper name, or by a general word joined to distinguishing circumstances; if unknown, it may be pointed out to the senses; when beyond the reach of the senses it may be picked out by an imperfect but true description. | |
From: Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], 1) | |
A reaction: [compressed] If Putnam, Kripke and Donnellan had read this paragraph they could have save themselves a lot of work! I take reference to be the activity of speakers and writers, and these are the main tools of the trade. |
23645 | A word's meaning is the thing conceived, as fixed by linguistic experts [Reid] |
Full Idea: The meaning of a word (such as 'felony') is the thing conceived; and that meaning is the conception affixed to it by those who best understand the language. | |
From: Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], 1) | |
A reaction: He means legal experts. This is precisely that same as Putnam's account of the meaning of 'elm tree'. His discussion here of reference is the earliest I have encountered, and it is good common sense (for which Reid is famous). |
11206 | The mind constructs complete attributions, based on the unified elements of the real world [Aquinas] |
Full Idea: Attribution is something mind brings to completion by constructing propositional connections and disconnections, basing itself on real-world unity possessed by the things being attributed to one another. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.102) | |
A reaction: This compromise story seems to me to be exactly right. I take it that we respond to the real joints of nature, but using thought and language which is riddled with convention. |
11207 | A cause can exist without its effect, but the effect cannot exist without its cause [Aquinas] |
Full Idea: When things are so related that one causes the other to exist, the cause can exist without what it causes but not vice versa. | |
From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.103) | |
A reaction: This is open to question, if causes are supposed to be sufficient for effects. Presumably Aquinas would support the view that if the cause had not been, the effect would not have happened. But the current idea indicates the priority relation. |