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All the ideas for 'Parmenides', 'First-Order Logic' and 'Ontology'

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66 ideas

2. Reason / A. Nature of Reason / 1. On Reason
When questions are doubtful we should concentrate not on objects but on ideas of the intellect [Plato]
     Full Idea: Doubtful questions should not be discussed in terms of visible objects or in relation to them, but only with reference to ideas conceived by the intellect.
     From: Plato (Parmenides [c.364 BCE], 135e)
2. Reason / B. Laws of Thought / 5. Opposites
Opposites are as unlike as possible [Plato]
     Full Idea: Opposites are as unlike as possible.
     From: Plato (Parmenides [c.364 BCE], 159a)
2. Reason / C. Styles of Reason / 1. Dialectic
Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic [Hegel on Plato]
     Full Idea: Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic.
     From: comment on Plato (Parmenides [c.364 BCE]) by Georg W.F.Hegel - Phenomenology of Spirit Pref 71
     A reaction: It is a long way from the analytic tradition of philosophy to be singling out a classic text for its 'artistic' achievement. Eventually we may even look back on, say, Kripke's 'Naming and Necessity' and see it in that light.
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
The modal logic of C.I.Lewis was only interpreted by Kripke and Hintikka in the 1960s [Jacquette]
     Full Idea: The modal syntax and axiom systems of C.I.Lewis (1918) were formally interpreted by Kripke and Hintikka (c.1965) who, using Z-F set theory, worked out model set-theoretical semantics for modal logics and quantified modal logics.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: A historical note. The big question is always 'who cares?' - to which the answer seems to be 'lots of people', if they are interested in precision in discourse, in artificial intelligence, and maybe even in metaphysics. Possible worlds started here.
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W]
     Full Idea: A logic is a collection of closely related artificial languages, and its older meaning is the study of the rules of sound argument. The languages can be used as a framework for studying rules of argument.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.1)
     A reaction: [Hodges then says he will stick to the languages] The suspicion is that one might confine the subject to the artificial languages simply because it is easier, and avoids the tricky philosophical questions. That approximates to computer programming.
Logic describes inferences between sentences expressing possible properties of objects [Jacquette]
     Full Idea: It is fundamental that logic depends on logical possibilities, in which logically possible properties are predicated of logically possible objects. Logic describes inferential structures among sentences expressing the predication of properties to objects.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: If our imagination is the only tool we have for assessing possibilities, this leaves the domain of logic as being a bit subjective. There is an underlying Platonism to the idea, since inferences would exist even if nothing else did.
5. Theory of Logic / C. Ontology of Logic / 2. Platonism in Logic
Logic is not just about signs, because it relates to states of affairs, objects, properties and truth-values [Jacquette]
     Full Idea: At one level logic can be regarded as a theory of signs and formal rules, but we cannot neglect the meaning of propositions as they relate to states of affairs, and hence to possible properties and objects... there must be the possibility of truth-values.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: Thus if you define logical connectives by truth tables, you need the concept of T and F. You could, though, regard those too as purely formal (like 1 and 0 in electronics). But how do you decide which propositions are 1, and which are 0?
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / c. Theory of definite descriptions
On Russell's analysis, the sentence "The winged horse has wings" comes out as false [Jacquette]
     Full Idea: It is infamous that on Russell's analysis the sentences "The winged horse has wings" and "The winged horse is a horse" are false, because in the extant domain of actual existent entities there contingently exist no winged horses
     From: Dale Jacquette (Ontology [2002], Ch. 6)
     A reaction: This is the best objection I have heard to Russell's account of definite descriptions. The connected question is whether 'quantifies over' is really a commitment to existence. See Idea 6067.
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W]
     Full Idea: To have a truth-value, a first-order formula needs an 'interpretation' (I) of its constants, and a 'valuation' (ν) of its variables. Something in the world is attached to the constants; objects are attached to variables.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.3)
There are three different standard presentations of semantics [Hodges,W]
     Full Idea: Semantic rules can be presented in 'Tarski style', where the interpretation-plus-valuation is reduced to the same question for simpler formulas, or the 'Henkin-Hintikka style' in terms of games, or the 'Barwise-Etchemendy style' for computers.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.3)
     A reaction: I haven't yet got the hang of the latter two, but I note them to map the territory.
I |= φ means that the formula φ is true in the interpretation I [Hodges,W]
     Full Idea: I |= φ means that the formula φ is true in the interpretation I.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.5)
     A reaction: [There should be no space between the vertical and the two horizontals!] This contrasts with |-, which means 'is proved in'. That is a syntactic or proof-theoretic symbol, whereas |= is a semantic symbol (involving truth).
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W]
     Full Idea: Downward Löwenheim-Skolem (the weakest form): If L is a first-order language with at most countably many formulas, and T is a consistent theory in L. Then T has a model with at most countably many elements.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.10)
Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W]
     Full Idea: Upward Löwenheim-Skolem: every first-order theory with infinite models has arbitrarily large models.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.10)
5. Theory of Logic / K. Features of Logics / 6. Compactness
If a first-order theory entails a sentence, there is a finite subset of the theory which entails it [Hodges,W]
     Full Idea: Compactness Theorem: suppose T is a first-order theory, ψ is a first-order sentence, and T entails ψ. Then there is a finite subset U of T such that U entails ψ.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.10)
     A reaction: If entailment is possible, it can be done finitely.
5. Theory of Logic / L. Paradox / 3. Antinomies
Plato found antinomies in ideas, Kant in space and time, and Bradley in relations [Plato, by Ryle]
     Full Idea: Plato (in 'Parmenides') shows that the theory that 'Eide' are substances, and Kant that space and time are substances, and Bradley that relations are substances, all lead to aninomies.
     From: report of Plato (Parmenides [c.364 BCE]) by Gilbert Ryle - Are there propositions? 'Objections'
Plato's 'Parmenides' is perhaps the best collection of antinomies ever made [Russell on Plato]
     Full Idea: Plato's 'Parmenides' is perhaps the best collection of antinomies ever made.
     From: comment on Plato (Parmenides [c.364 BCE]) by Bertrand Russell - The Principles of Mathematics §337
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / d. Russell's paradox
Can a Barber shave all and only those persons who do not shave themselves? [Jacquette]
     Full Idea: The Barber Paradox refers to the non-existent property of being a barber who shaves all and only those persons who do not shave themselves.
     From: Dale Jacquette (Ontology [2002], Ch. 9)
     A reaction: [Russell spotted this paradox, and it led to his Theory of Types]. This paradox may throw light on the logic of indexicals. What does "you" mean when I say to myself "you idiot!"? If I can behave as two persons, so can the barber.
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
A 'set' is a mathematically well-behaved class [Hodges,W]
     Full Idea: A 'set' is a mathematically well-behaved class.
     From: Wilfrid Hodges (First-Order Logic [2001], 1.6)
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
One is, so numbers exist, so endless numbers exist, and each one must partake of being [Plato]
     Full Idea: If one is, there must also necessarily be number - Necessarily - But if there is number, there would be many, and an unlimited multitude of beings. ..So if all partakes of being, each part of number would also partake of it.
     From: Plato (Parmenides [c.364 BCE], 144a)
     A reaction: This seems to commit to numbers having being, then to too many numbers, and hence to too much being - but without backing down and wondering whether numbers had being after all. Aristotle disagreed.
7. Existence / A. Nature of Existence / 3. Being / a. Nature of Being
To grasp being, we must say why something exists, and why there is one world [Jacquette]
     Full Idea: We grasp the concept of being only when we have satisfactorily answered the question why there is something rather than nothing and why there is only one logically contingent actual world.
     From: Dale Jacquette (Ontology [2002], Conclusion)
     A reaction: See Ideas 7688 and 7692 for a glimpse of Jacquette's answer. Personally I don't yet have a full grasp of the concept of being, but I'm sure I'll get there if I only work a bit harder.
7. Existence / A. Nature of Existence / 3. Being / c. Becoming
The one was and is and will be and was becoming and is becoming and will become [Plato]
     Full Idea: The one was and is and will be and was becoming and is becoming and will become.
     From: Plato (Parmenides [c.364 BCE], 155d)
7. Existence / A. Nature of Existence / 3. Being / f. Primary being
Plato's Parmenides has a three-part theory, of Primal One, a One-Many, and a One-and-Many [Plato, by Plotinus]
     Full Idea: The Platonic Parmenides is more exact [than Parmenides himself]; the distinction is made between the Primal One, a strictly pure Unity, and a secondary One which is a One-Many, and a third which is a One-and-Many.
     From: report of Plato (Parmenides [c.364 BCE]) by Plotinus - The Enneads 5.1.08
     A reaction: Plotinus approves of this three-part theory. Parmenides has the problem that the highest Being contains no movement. By placing the One outside Being you can give it powers which an existent thing cannot have. Cf the concept of God.
7. Existence / A. Nature of Existence / 5. Reason for Existence
Being is maximal consistency [Jacquette]
     Full Idea: Being is maximal consistency.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: You'll have to read Ch.2 of Jacquette to see what this is all about, but as it stands it is a lovely slogan, and a wonderful googly/curve ball to propel at Parmenides or Heidegger.
Existence is completeness and consistency [Jacquette]
     Full Idea: A combinatorial ontology holds that existence is nothing more or less than completeness and consistency, or what is also called 'maximal consistency'.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: You'll have to read Jacquette to understand this one! The claim is that existence is to be defined in terms of logic (and whatever is required for logic). I take this to be a bit Platonist (rather than conventionalist) about logic.
7. Existence / D. Theories of Reality / 1. Ontologies
Ontology is the same as the conceptual foundations of logic [Jacquette]
     Full Idea: The principles of pure philosophical ontology are indistinguishable ... from the conceptual foundations of logic.
     From: Dale Jacquette (Ontology [2002], Pref)
     A reaction: I would take Russell to be an originator of this view. If the young Wittgenstein showed that the foundations of logic are simply conventional (truth tables), this seems to make ontology conventional too, which sounds very odd indeed (to me).
7. Existence / D. Theories of Reality / 3. Reality
Absolute ideas, such as the Good and the Beautiful, cannot be known by us [Plato]
     Full Idea: The absolute good and the beautiful and all which we conceive to be absolute ideas are unknown to us.
     From: Plato (Parmenides [c.364 BCE], 134c)
7. Existence / D. Theories of Reality / 11. Ontological Commitment / a. Ontological commitment
Ontology must include the minimum requirements for our semantics [Jacquette]
     Full Idea: The entities included in a theoretical ontology are those minimally required for an adequate philosophical semantics. ...These are the objects that we say exist, to which we are ontologically committed.
     From: Dale Jacquette (Ontology [2002], Pref)
     A reaction: Worded with exquisite care! He does not say that ontology is reducible to semantics (which is a silly idea). We could still be committed, as in a ghost story, to existence of some 'nameless thing'. Things utterly beyond our ken might exist.
7. Existence / E. Categories / 3. Proposed Categories
Logic is based either on separate objects and properties, or objects as combinations of properties [Jacquette]
     Full Idea: Logic involves the possibilities of predicating properties of objects in a conceptual scheme wherein either objects and properties are included in altogether separate categories, or objects are reducible to combinations of properties.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: In the first view, he says that objects are just 'logical pegs' for properties. Objects can't be individuated without properties. But combinations of properties would seem to need essences, or else they are too unstable to count as objects.
Reduce states-of-affairs to object-property combinations, and possible worlds to states-of-affairs [Jacquette]
     Full Idea: We can reduce references to states-of-affairs to object-property combinations, and we can reduce logically possible worlds to logically possible states-of-affairs combinations.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: If we further reduce object-property combinations to mere combinations of properties (Idea 7683), then we have reduced our ontology to nothing but properties. Wow. We had better be very clear, then, about what a property is. I'm not.
8. Modes of Existence / B. Properties / 11. Properties as Sets
If classes can't be eliminated, and they are property combinations, then properties (universals) can't be either [Jacquette]
     Full Idea: If classes alone cannot be eliminated from ontology on Quine's terms, and if classes are defined as property combinations, then neither are all properties, universals in the tradition sense, entirely eliminable.
     From: Dale Jacquette (Ontology [2002], Ch. 9)
     A reaction: If classes were totally conventional (and there was no such things as a 'natural' class) then you might admit something to a class without knowing its properties (as 'the thing in the box').
8. Modes of Existence / D. Universals / 2. Need for Universals
If you deny that each thing always stays the same, you destroy the possibility of discussion [Plato]
     Full Idea: If a person denies that the idea of each thing is always the same, he will utterly destroy the power of carrying on discussion.
     From: Plato (Parmenides [c.364 BCE], 135c)
You must always mean the same thing when you utter the same name [Plato]
     Full Idea: You must always mean the same thing when you utter the same name.
     From: Plato (Parmenides [c.364 BCE], 147d)
8. Modes of Existence / D. Universals / 6. Platonic Forms / a. Platonic Forms
It would be absurd to think there were abstract Forms for vile things like hair, mud and dirt [Plato]
     Full Idea: Are there abstract ideas for such things as hair, mud and dirt, which are particularly vile and worthless? That would be quite absurd.
     From: Plato (Parmenides [c.364 BCE], 130d)
The concept of a master includes the concept of a slave [Plato]
     Full Idea: Mastership in the abstract is mastership of slavery in the abstract.
     From: Plato (Parmenides [c.364 BCE], 133e)
If admirable things have Forms, maybe everything else does as well [Plato]
     Full Idea: It is troubling that if admirable things have abstract ideas, then perhaps everything else must have ideas as well.
     From: Plato (Parmenides [c.364 BCE], 130d)
If absolute ideas existed in us, they would cease to be absolute [Plato]
     Full Idea: None of the absolute ideas exists in us, because then it would no longer be absolute.
     From: Plato (Parmenides [c.364 BCE], 133c)
Greatness and smallness must exist, to be opposed to one another, and come into being in things [Plato]
     Full Idea: These two ideas, greatness and smallness, exist, do they not? For if they did not exist, they could not be opposites of one another, and could not come into being in things.
     From: Plato (Parmenides [c.364 BCE], 149e)
Plato moves from Forms to a theory of genera and principles in his later work [Plato, by Frede,M]
     Full Idea: It seems to me that Plato in the later dialogues, beginning with the second half of 'Parmenides', wants to substitute a theory of genera and theory of principles that constitute these genera for the earlier theory of forms.
     From: report of Plato (Parmenides [c.364 BCE]) by Michael Frede - Title, Unity, Authenticity of the 'Categories' V
     A reaction: My theory is that the later Plato came under the influence of the brilliant young Aristotle, and this idea is a symptom of it. The theory of 'principles' sounds like hylomorphism to me.
8. Modes of Existence / D. Universals / 6. Platonic Forms / b. Partaking
Participation is not by means of similarity, so we are looking for some other method of participation [Plato]
     Full Idea: Participation is not by means of likeness, so we must seek some other method of participation.
     From: Plato (Parmenides [c.364 BCE], 133a)
If things partake of ideas, this implies either that everything thinks, or that everything actually is thought [Plato]
     Full Idea: If all things partake of ideas, must either everything be made of thoughts and everything thinks, or everything is thought, and so can't think?
     From: Plato (Parmenides [c.364 BCE], 132c)
Each idea is in all its participants at once, just as daytime is a unity but in many separate places at once [Plato]
     Full Idea: Just as day is in many places at once, but not separated from itself, so each idea might be in all its participants at once.
     From: Plato (Parmenides [c.364 BCE], 131b)
If things are made alike by participating in something, that thing will be the absolute idea [Plato]
     Full Idea: That by participation in which like things are made like, will be the absolute idea, will it not?
     From: Plato (Parmenides [c.364 BCE], 132e)
The whole idea of each Form must be found in each thing which participates in it [Plato]
     Full Idea: The whole idea of each form (of beauty, justice etc) must be found in each thing which participates in it.
     From: Plato (Parmenides [c.364 BCE], 131a)
8. Modes of Existence / D. Universals / 6. Platonic Forms / c. Self-predication
Nothing can be like an absolute idea, because a third idea intervenes to make them alike (leading to a regress) [Plato]
     Full Idea: It is impossible for anything to be like an absolute idea, because a third idea will appear to make them alike, and if that is like anything, it will lead to another idea, and so on.
     From: Plato (Parmenides [c.364 BCE], 133a)
If absolute greatness and great things are seen as the same, another thing appears which makes them seem great [Plato]
     Full Idea: If you regard the absolute great and the many great things in the same way, will not another appear beyond, by which all these must appear to be great?
     From: Plato (Parmenides [c.364 BCE], 132a)
9. Objects / A. Existence of Objects / 1. Physical Objects
An object is a predication subject, distinguished by a distinctive combination of properties [Jacquette]
     Full Idea: To be an object is to be a predication subject, and to be this as opposed to that particular object, whether existent or not, is to have a distinctive combination of properties.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: The last part depends on Leibniz's Law. The difficulty is that two objects may only be distinguishable by being in different places, and location doesn't look like a property. Cf. Idea 5055.
9. Objects / A. Existence of Objects / 2. Abstract Objects / c. Modern abstracta
Numbers, sets and propositions are abstract particulars; properties, qualities and relations are universals [Jacquette]
     Full Idea: Roughly, numbers, sets and propositions are assumed to be abstract particulars, while properties, including qualities and relations, are usually thought to be universals.
     From: Dale Jacquette (Ontology [2002], Ch. 9)
     A reaction: There is an interesting nominalist project of reducing all of these to particulars. Numbers to patterns, sets to their members, propositions to sentences, properties to causal powers, relations to, er, something else.
9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
Parts must belong to a created thing with a distinct form [Plato]
     Full Idea: The part would not be the part of many things or all, but of some one character ['ideas'] and of some one thing, which we call a 'whole', since it has come to be one complete [perfected] thing composed [created] of all.
     From: Plato (Parmenides [c.364 BCE], 157d)
     A reaction: A serious shot by Plato at what identity is. Harte quotes it (125) and shows that 'character' is Gk 'idea', and 'composed' will translate as 'created'. 'Form' links this Platonic passage to Aristotle's hylomorphism.
9. Objects / C. Structure of Objects / 5. Composition of an Object
In Parmenides, if composition is identity, a whole is nothing more than its parts [Plato, by Harte,V]
     Full Idea: At the heart of the 'Parmenides' puzzles about composition is the thesis that composition is identity. Considered thus, a whole adds nothing to an ontology that already includes its parts
     From: report of Plato (Parmenides [c.364 BCE]) by Verity Harte - Plato on Parts and Wholes 2.5
     A reaction: There has to be more to a unified identity that mere proximity of the parts. When do parts come together, and when do they actually 'compose' something?
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
Plato says only a one has parts, and a many does not [Plato, by Harte,V]
     Full Idea: In 'Parmenides' it is argued that a part cannot be part of a many, but must be part of something one.
     From: report of Plato (Parmenides [c.364 BCE], 157c) by Verity Harte - Plato on Parts and Wholes 3.2
     A reaction: This looks like the right way to go with the term 'part'. We presuppose a unity before we even talk of its parts, so we can't get into contradictions and paradoxes about their relationships.
Anything which has parts must be one thing, and parts are of a one, not of a many [Plato]
     Full Idea: The whole of which the parts are parts must be one thing composed of many; for each of the parts must be part, not of a many, but of a whole.
     From: Plato (Parmenides [c.364 BCE], 157c)
     A reaction: This is a key move of metaphysics, and we should hang on to it. The other way madness lies.
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
It seems that the One must be composed of parts, which contradicts its being one [Plato]
     Full Idea: The One must be composed of parts, both being a whole and having parts. So on both grounds the One would thus be many and not one. But it must be not many, but one. So if the One will be one, it will neither be a whole, nor have parts.
     From: Plato (Parmenides [c.364 BCE], 137c09), quoted by Kathrin Koslicki - The Structure of Objects 5.2
     A reaction: This is the starting point for Plato's metaphysical discussion of objects. It seems to begin a line of thought which is completed by Aristotle, surmising that only an essential structure can bestow identity on a bunch of parts.
9. Objects / F. Identity among Objects / 6. Identity between Objects
Two things relate either as same or different, or part of a whole, or the whole of the part [Plato]
     Full Idea: Everything is surely related to everything as follows: either it is the same or different; or, if it is not the same or different, it would be related as part to whole or as whole to part.
     From: Plato (Parmenides [c.364 BCE], 146b)
     A reaction: This strikes me as a really helpful first step in trying to analyse the nature of identity. Two things are either two or (actually) one, or related mereologically.
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
The actual world is a consistent combination of states, made of consistent property combinations [Jacquette]
     Full Idea: The actual world is a maximally consistent state-of-affairs combination involving all and only the existent objects, which in turn exist because they are maximally consistent property combinations.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: [This extends Idea 7688]. This seems to invite the standard objections to the coherence theory of truth, such as Ideas 5422 and 4745. Is 'maximal consistency' merely a test for actuality, rather than an account of what actuality is?
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
The actual world is a maximally consistent combination of actual states of affairs [Jacquette]
     Full Idea: The actual world can be defined as a maximally consistent combination of actual states of affairs, or maximally consistent states-of-affairs combination.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: A key part of Jacquette's program of deriving ontological results from the foundations of logic. Is the counterfactual situation of my pen being three centimetres to the left of its current position a "less consistent" situation than the actual one?
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / c. Worlds as propositions
Do proposition-structures not associated with the actual world deserve to be called worlds? [Jacquette]
     Full Idea: Many modal logicians in their philosophical moments have raised doubts about whether structures of propositions not associated with the actual world deserved to be called worlds at all.
     From: Dale Jacquette (Ontology [2002], Ch. 2)
     A reaction: A good question. Consistency is obviously required, but we also need a lot of propositions before we would consider it a 'world'. Very remote but consistent worlds quickly become unimaginable. Does that matter?
We must experience the 'actual' world, which is defined by maximally consistent propositions [Jacquette]
     Full Idea: Conventional modal semantics, in which all logically possible worlds are defined in terms of maximally consistent proposition sets, has no choice except to allow that the actual world is the world we experience in sensation, or that we inhabit.
     From: Dale Jacquette (Ontology [2002], Ch. 9)
     A reaction: Jacquette dislikes this because he is seeking an account of ontology that doesn't, as so often, merely reduce to epistemology (e.g. Berkeley). See Idea 7691 for his preferred account.
15. Nature of Minds / B. Features of Minds / 5. Qualia / c. Explaining qualia
If qualia supervene on intentional states, then intentional states are explanatorily fundamental [Jacquette]
     Full Idea: If qualia supervene on intentional states, then intentionality is also more explanatorily fundamental than qualia.
     From: Dale Jacquette (Ontology [2002], Ch.10)
     A reaction: See Idea 7272 for opposite view. Maybe intentional states are large mental objects of which we are introspectively aware, but which are actually composed of innumerable fine-grained qualia. Intentional states would only explain qualia if they caused them.
17. Mind and Body / E. Mind as Physical / 2. Reduction of Mind
Reduction of intentionality involving nonexistent objects is impossible, as reduction must be to what is actual [Jacquette]
     Full Idea: If intentionality sometimes involves a relation to nonexistent objects, like my dreamed-of visit to a Greek island, then such thoughts cannot be explained physically or causally, because only actual physical entities and events can be mentioned.
     From: Dale Jacquette (Ontology [2002], Ch.10)
     A reaction: Unimpressive. Thoughts of a Greek island will obviously reduce to memories of islands and Greece and travel brochures. Memory clearly retains past events in the present, and hence past events can be part of the material used in reductive accounts.
19. Language / D. Propositions / 1. Propositions
The extreme views on propositions are Frege's Platonism and Quine's extreme nominalism [Jacquette]
     Full Idea: The extreme ontological alternatives with respect to the metaphysics of propositions are a Fregean Platonism (his "gedanken", 'thoughts'), and a radical nominalism or inscriptionalism, as in Quine, where they are just marks related to stimuli.
     From: Dale Jacquette (Ontology [2002], Ch. 9)
     A reaction: Personally I would want something between the two - that propositions are brain events of a highly abstract kind. I say that introspection reveals pre-linguistic thoughts, which are propositions. A proposition is an intentional state.
25. Social Practice / E. Policies / 5. Education / c. Teaching
Only a great person can understand the essence of things, and an even greater person can teach it [Plato]
     Full Idea: Only a man of very great natural gifts will be able to understand that everything has a class and absolute essence, and an even more wonderful man can teach this.
     From: Plato (Parmenides [c.364 BCE], 135a)
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / d. The unlimited
The unlimited has no shape and is endless [Plato]
     Full Idea: The unlimited partakes neither of the round nor of the straight, because it has no ends nor edges.
     From: Plato (Parmenides [c.364 BCE], 137e)
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / e. The One
Some things do not partake of the One [Plato]
     Full Idea: The others cannot partake of the one in any way; they can neither partake of it nor of the whole.
     From: Plato (Parmenides [c.364 BCE], 159d)
     A reaction: Compare Idea 231
The only movement possible for the One is in space or in alteration [Plato]
     Full Idea: If the One moves it either moves spatially or it is altered, since these are the only motions.
     From: Plato (Parmenides [c.364 BCE], 138b)
Everything partakes of the One in some way [Plato]
     Full Idea: The others are not altogether deprived of the one, for they partake of it in some way.
     From: Plato (Parmenides [c.364 BCE], 157c)
     A reaction: Compare Idea 233.
28. God / B. Proving God / 2. Proofs of Reason / a. Ontological Proof
We couldn't discuss the non-existence of the One without knowledge of it [Plato]
     Full Idea: There must be knowledge of the one, or else not even the meaning of the words 'if the one does not exist' would be known.
     From: Plato (Parmenides [c.364 BCE], 160d)