29 ideas
| 18450 | Philosophy has its own mode of death, by separating soul from body [Porphyry] |
| Full Idea: There is a double death. One, known by all men, consists in the separation of the body with the soul; the other, characteristic of philosophers, results in the separation of the soul from the body. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 1Enn9 3) |
| 13338 | '"It is snowing" is true if and only if it is snowing' is a partial definition of the concept of truth [Tarski] |
| Full Idea: Statements of the form '"it is snowing" is true if and only if it is snowing' and '"the world war will begin in 1963" is true if and only if the world war will being in 1963' can be regarded as partial definitions of the concept of truth. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.404) | |
| A reaction: The key word here is 'partial'. Truth is defined, presumably, when every such translation from the object language has been articulated, which is presumably impossible, given the infinity of concatenated phrases possible in a sentence. |
| 13337 | A language: primitive terms, then definition rules, then sentences, then axioms, and finally inference rules [Tarski] |
| Full Idea: For a language, we must enumerate the primitive terms, and the rules of definition for new terms. Then we must distinguish the sentences, and separate out the axioms from amng them, and finally add rules of inference. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.402) | |
| A reaction: [compressed] This lays down the standard modern procedure for defining a logical language. Once all of this is in place, we then add a semantics and we are in business. Natural deduction tries to do without the axioms. |
| 13335 | Semantics is the concepts of connections of language to reality, such as denotation, definition and truth [Tarski] |
| Full Idea: Semantics is the totality of considerations concerning concepts which express connections between expressions of a language and objects and states of affairs referred to by these expressions. Examples are denotation, satisfaction, definition and truth. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.401) | |
| A reaction: Interestingly, he notes that it 'is not commonly recognised' that truth is part of semantics. Nowadays truth seems to be the central concept in most semantics. |
| 13336 | A language containing its own semantics is inconsistent - but we can use a second language [Tarski] |
| Full Idea: People have not been aware that the language about which we speak need by no means coincide with the language in which we speak. ..But the language which contains its own semantics must inevitably be inconsistent. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.402) | |
| A reaction: It seems that Tarski was driven to propose the metalanguage approach mainly by the Liar Paradox. |
| 13339 | A sentence is satisfied when we can assert the sentence when the variables are assigned [Tarski] |
| Full Idea: Here is a partial definition of the concept of satisfaction: John and Peter satisfy the sentential function 'X and Y are brothers' if and only if John and Peter are brothers. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.405) | |
| A reaction: Satisfaction applies to open sentences and truth to closed sentences (with named objects). He uses the notion of total satisfaction to define truth. The example is a partial definition, not just an illustration. |
| 13340 | Satisfaction is the easiest semantical concept to define, and the others will reduce to it [Tarski] |
| Full Idea: It has been found useful in defining semantical concepts to deal first with the concept of satisfaction; both because the definition of this concept presents relatively few difficulties, and because the other semantical concepts are easily reduced to it. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.406) | |
| A reaction: See Idea 13339 for his explanation of satisfaction. We just say that a open sentence is 'acceptable' or 'assertible' (or even 'true') when particular values are assigned to the variables. Then sentence is then 'satisfied'. |
| 13341 | Using the definition of truth, we can prove theories consistent within sound logics [Tarski] |
| Full Idea: Using the definition of truth we are in a position to carry out the proof of consistency for deductive theories in which only (materially) true sentences are (formally) provable. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.407) | |
| A reaction: This is evidently what Tarski saw as the most important first fruit of his new semantic theory of truth. |
| 18451 | The presence of the incorporeal is only known by certain kinds of disposition [Porphyry] |
| Full Idea: Being everywhere and nowhere, the incorporeal, wherever it happens to be, betrays its presence only by a certain kind of disposition. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 4Enn3 21(20)) | |
| A reaction: There is a mystical or dualist view of fundamental powers, as the spiritual engine which drives passive physical nature. It's rubbish of course, but if powers are primitive in a naturalistic theory, it is not a view which can be refuted. |
| 18459 | Diversity arises from the power of unity [Porphyry] |
| Full Idea: Diversity is born of the development of the power of unity. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn5 42) | |
| A reaction: I doubt whether even Porphyry understood this, but we might say that once the principle of unification enters into nature, it will inevitably result in diversity. One all-embracing unity would be indiscernible. |
| 18452 | Memory is not conserved images, but reproduction of previous thought [Porphyry] |
| Full Idea: Memory does not consist in preserving images. It is a faculty of reproducing the conceptions with which our soul has been occupied. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 5Enn6 25(2)) |
| 18453 | Intelligence is aware of itself, so the intelligence is both the thinker and the thought [Porphyry] |
| Full Idea: Since intelligence is intelligible for intelligence, intelligence is its own object. ...Intelligence, therefore, is simultaneously thinker and thought, all that thinks and all that is thought. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 5Enn3 32(5-7)) | |
| A reaction: This is a bit of a problem for Descartes, if the Cogito is taken as offering evidence (thought) for the existence of a thinker ('I'). Porphyry implies that the separation Descartes requires is impossible. |
| 18462 | The soul is everywhere and nowhere in the body, and must be its cause [Porphyry] |
| Full Idea: The soul is neither a body, nor in the body, but is only the cause of the body, because she is simultaneously everywhere and nowhere in the body. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn5 43) | |
| A reaction: This is the rather bewildering phenomenology of consciousness which persuaded Descartes of dualism. |
| 18463 | Successful introspection reveals the substrate along with the object of thought [Porphyry] |
| Full Idea: He who by thought can penetrate within his own substance, and can thus acquire knowledge of it, finds himself in this actualisation of knowledge and consciousness, where the substrate that knows is identical with the object that is known. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn5 44) | |
| A reaction: It seems remarkably that this ability is confidently asserted by Porphyry, and flatly denied by Hume. Were they just different people, or were they looking for different things, or was one of them deluded? |
| 18458 | The soul is bound to matter by the force of its own disposition [Porphyry] |
| Full Idea: The individual soul, which declines towards matter, is bound to the matter by the form which her disposition has made her choose. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn4 39) | |
| A reaction: This sounds like the soul is boss over the matter, and yet the soul is 'made' to choose union with matter. The Universal Soul is seen by Porphyr as the controller of the situation. |
| 18464 | Justice is each person fulfilling his function [Porphyry] |
| Full Idea: Justice, as has been rightly said, consists in each one fulfilling his [authentic and proper] function. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn5 44) | |
| A reaction: This is presumably a direct reference to the theory in Plato's 'Republic'. It makes the connection between virtue and function which I take to be basic to virtue theory, giving it a naturalistic advantaged over other theories. |
| 18448 | We should avoid the pleasures of love, or at least, should not enact our dreams [Porphyry] |
| Full Idea: The pleasures of love will not even involuntarily be tasted, at least, she will not allow herself to be drawn beyond the lights of fancy that occur in dreams. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 1Enn2 I.4) | |
| A reaction: Presumably erotic dreams are only tolerated because not much can be done about them. This brings out the puritanism of neo-platonism. |
| 18444 | Civil virtues make us behave benevolently, and thereby unite citizens [Porphyry] |
| Full Idea: The object of the civil virtues is to make us benevolent in our dealings with our fellow-human beings, and are so-called because they unite citizens. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 1Enn2 I.1) | |
| A reaction: Modern commentators underestimate the close link between ancient virtue and citizenship. It is hard for one person to have much of a notion of virtue if they live on a desert island, beyond caring for personal health. |
| 18445 | Civil virtues control the passions, and make us conform to our nature [Porphyry] |
| Full Idea: The civil virtues moderate the passions; their object is to teach us to live in conformity with the laws of human nature. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 1Enn2 I.2) | |
| A reaction: The link with human nature is basic to virtue theory, but this proposal is rather too vague. Are passions not part of the laws of human nature? |
| 18446 | Purificatory virtues detach the soul completely from the passions [Porphyry] |
| Full Idea: The object of the 'purificatory' virtues is to detach the soul completely from the passions. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 1Enn2 I.4) | |
| A reaction: This is an aspect of virtue theory which doesn't appear in Aristotle. He is in favour of rational control of the passions, but not of totally abandoning them. The neo-platonists are much more puritanical. They seem to go against human nature. |
| 18447 | There are practical, purificatory, contemplative, and exemplary virtues [Porphyry] |
| Full Idea: The practical virtues make man virtuous; the purificatory virtues make man divine....; the contemplative virtues defiy; while the exemplary virtues make a man the parent of divinities. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 1Enn2 I.4) | |
| A reaction: I like the idea of the 'exemplary' virtues. I think an entire theory of morality could be built on the notion that we are all role-models for one another. |
| 18456 | Unified real existence is neither great nor small, though greatness and smallness participate in it [Porphyry] |
| Full Idea: By its identity and numerical unity, real existence is neither great nor small, neither very large nor very small, though it causes even greatest and smallest to participate in its nature. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn4 37(5)) | |
| A reaction: Note the platonic word 'participate' [metechein], suggesting that he is talking about the Form of Existence here. Note also that we have 'real' existence here, implying a lesser type of existence that participates in it. |
| 16707 | Cold and hot are the swiftness and slowness of corpuscular motion [Beeckman] |
| Full Idea: There is no doubt that the nature of cold and hot are taken from the swiftness and slowness of the motion of corpuscules. | |
| From: Isaac Beeckman (Journals [1617], I:132), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 19.6 | |
| A reaction: This is so right it takes your breath away. For 'corpuscles' we should normally read 'molecules'. Atomism is a further refinement. This is the rejection of the orthodox view of separate qualities. |
| 18454 | Time is the circular movement of the soul [Porphyry] |
| Full Idea: It is the circular movement of the soul that constitutes time, just as the permanence of intelligence in itself constitutes eternity. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 5Enn3 32(5-7)) | |
| A reaction: Plato loved circles. If you think time is subjective, this is trying to express your intuition. Personally I think it is nonsense |
| 18455 | Some think time is seen at rest, as well as in movement [Porphyry] |
| Full Idea: Some have believed that time manifested in rest as well as in movement. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 5Enn3 32(5-7)) | |
| A reaction: If you like this idea, you should see Shoemaker's lovely three-worlds thought experiment. |
| 18460 | God is nowhere, and hence everywhere [Porphyry] |
| Full Idea: The divinity is everywhere because it is nowhere. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn5 43) |
| 18461 | Everything existing proceeds from divinity, and is within divinity [Porphyry] |
| Full Idea: All things that possess or do not possess existence proceed from divinity, and are within divinity. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn5 43) | |
| A reaction: Nice to see Porphyry endorsing Meinongian objects. I doubt whether he counts as a pantheist, but this is a very pantheistic remark. |
| 18449 | Nature binds or detaches body to soul, but soul itself joins and detaches soul from body [Porphyry] |
| Full Idea: Nature binds the body to the soul, but it is the soul herself that has bound herself to the body. It, therefore, belongs to nature to detach the body from the soul, while it is the soul herself that detaches herself from the body. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 1Enn9 2) | |
| A reaction: Baffling. What happens if there is a conflict? I suppose either party can cancel the bargain, but who wins when they disagree? |
| 18457 | Individual souls are all connected, though distinct, and without dividing universal Soul [Porphyry] |
| Full Idea: Individual souls are distinct without being separated from each other, and without dividing the universal Soul into a number of parts; they are united to each other without becoming confused. | |
| From: Porphyry (Launching Points to the Realm of the Mind [c.280], 6Enn4 39) | |
| A reaction: This sounds like Jung's theory that there is a universal subconscious which links us all together. Taken literally, I assume it is nonsense. As an invitation to acknowledge how much we all have in common, it is a nice corrective to liberal individualism. |