Combining Texts

All the ideas for 'The Evolution of Modern Metaphysics', 'First-Order Modal Logic' and 'Letters from a Stoic'

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78 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
Wisdom does not lie in books, and unread people can also become wise [Seneca]
     Full Idea: What grounds could I possibly have for supposing that a person who has no acquaintance with books will never be a wise man? For wisdom does not lie in books.
     From: Seneca the Younger (Letters from a Stoic [c.60], 088)
     A reaction: A useful warning to the likes of me, who may have retreated from the hurly-burly of the agora (see Callicles in Plato's 'Gorgias'), under the illusion that detachment is needed for wisdom. Maybe involvement is needed for wisdom.
1. Philosophy / A. Wisdom / 2. Wise People
Wise people escape necessity by willing it [Seneca]
     Full Idea: There is nothing a wise man does reluctantly; he escapes necessity because he wills what necessity is going to force on him.
     From: Seneca the Younger (Letters from a Stoic [c.60], 054)
     A reaction: He is discussing death in this letter. The difficulty here is sliding into fatalism. For instance, if you are informed that you have cancer, it is tempting to become 'wise' and will your own death, but lots of people fight it, and win.
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
Philosophy aims at happiness [Seneca]
     Full Idea: Philosophy takes as her aim the state of happiness.
     From: Seneca the Younger (Letters from a Stoic [c.60], 090)
     A reaction: A startlingly forthright view. It seems to neglect what I take to be the main aim of philosophy, which is to achieve understanding. I presume true happiness would follow from that. Seneca must now explain why soporific pleasure is wrong.
What philosophy offers humanity is guidance [Seneca]
     Full Idea: Shall I tell you what philosophy holds out for humanity? Counsel.
     From: Seneca the Younger (Letters from a Stoic [c.60], 048)
     A reaction: See Quine for a flat modern denial of this claim (Idea 9764). There is a modern tendency to see ethics and political thought operating at a meta- or metameta- level. I take the main ethical theories to be very illuminating of real life.
1. Philosophy / E. Nature of Metaphysics / 1. Nature of Metaphysics
Metaphysics is the most general attempt to make sense of things [Moore,AW]
     Full Idea: Metaphysics is the most general attempt to make sense of things.
     From: A.W. Moore (The Evolution of Modern Metaphysics [2012], Intro)
     A reaction: This is the first sentence of Moore's book, and a touchstone idea all the way through. It stands up well, because it says enough without committing to too much. I have to agree with it. It implies explanation as the key. I like generality too.
1. Philosophy / F. Analytic Philosophy / 3. Analysis of Preconditions
That something is a necessary condition of something else doesn't mean it caused it [Seneca]
     Full Idea: There's no reason for you to assume that, X being something without which Y could never have come about, Y came about as a result of the assistance of X.
     From: Seneca the Younger (Letters from a Stoic [c.60], 088)
     A reaction: This thought originates with Carneades, reported by Cicero. This is a clear message to the likes of Mackie, who are in danger of thinking that giving the preconditions of something is sufficient to give its causes.
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Even philosophers have got bogged down in analysing tiny bits of language [Seneca]
     Full Idea: Even the philosophers have descended to the level of drawing distinctions between the uses of different syllables and discussing the proper meanings of prepositions and conjunctions.
     From: Seneca the Younger (Letters from a Stoic [c.60], 088)
     A reaction: How wonderfully prescient! The vast industry of modern philosophy of language exactly fits Seneca's description. I don't quite share his contempt, of course, and I think Seneca would have a bit of sympathy with modern analysis (just a bit!).
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
Each line of a truth table is a model [Fitting/Mendelsohn]
     Full Idea: Each line of a truth table is, in effect, a model.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.6)
     A reaction: I find this comment illuminating. It is being connected with the more complex models of modal logic. Each line of a truth table is a picture of how the world might be.
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / a. Symbols of ML
Modal logic adds □ (necessarily) and ◊ (possibly) to classical logic [Fitting/Mendelsohn]
     Full Idea: For modal logic we add to the syntax of classical logic two new unary operators □ (necessarily) and ◊ (possibly).
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.3)
We let 'R' be the accessibility relation: xRy is read 'y is accessible from x' [Fitting/Mendelsohn]
     Full Idea: We let 'R' be the accessibility relation: xRy is read 'y is accessible from x'.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.5)
The symbol ||- is the 'forcing' relation; 'Γ ||- P' means that P is true in world Γ [Fitting/Mendelsohn]
     Full Idea: The symbol ||- is used for the 'forcing' relation, as in 'Γ ||- P', which means that P is true in world Γ.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.6)
The prefix σ names a possible world, and σ.n names a world accessible from that one [Fitting/Mendelsohn]
     Full Idea: A 'prefix' is a finite sequence of positive integers. A 'prefixed formula' is an expression of the form σ X, where σ is a prefix and X is a formula. A prefix names a possible world, and σ.n names a world accessible from that one.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / b. Terminology of ML
A 'constant' domain is the same for all worlds; 'varying' domains can be entirely separate [Fitting/Mendelsohn]
     Full Idea: In 'constant domain' semantics, the domain of each possible world is the same as every other; in 'varying domain' semantics, the domains need not coincide, or even overlap.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 4.5)
Modern modal logic introduces 'accessibility', saying xRy means 'y is accessible from x' [Fitting/Mendelsohn]
     Full Idea: Modern modal logic takes into consideration the way the modal relates the possible worlds, called the 'accessibility' relation. .. We let R be the accessibility relation, and xRy reads as 'y is accessible from x.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.5)
     A reaction: There are various types of accessibility, and these define the various modal logics.
A 'model' is a frame plus specification of propositions true at worlds, written < G,R,||- > [Fitting/Mendelsohn]
     Full Idea: A 'model' is a frame plus a specification of which propositional letters are true at which worlds. It is written as , where ||- is a relation between possible worlds and propositional letters. So Γ ||- P means P is true at world Γ.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.6)
A 'frame' is a set G of possible worlds, with an accessibility relation R, written < G,R > [Fitting/Mendelsohn]
     Full Idea: A 'frame' consists of a non-empty set G, whose members are generally called possible worlds, and a binary relation R, on G, generally called the accessibility relation. We say the frame is the pair so that a single object can be talked about.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.6)
Accessibility relations can be 'reflexive' (self-referring), 'transitive' (carries over), or 'symmetric' (mutual) [Fitting/Mendelsohn]
     Full Idea: A relation R is 'reflexive' if every world is accessible from itself; 'transitive' if the first world is related to the third world (ΓRΔ and ΔRΩ → ΓRΩ); and 'symmetric' if the accessibility relation is mutual.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.7)
     A reaction: The different systems of modal logic largely depend on how these accessibility relations are specified. There is also the 'serial' relation, which just says that any world has another world accessible to it.
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / c. Derivation rules of ML
S5: a) if n ◊X then kX b) if n ¬□X then k ¬X c) if n □X then k X d) if n ¬◊X then k ¬X [Fitting/Mendelsohn]
     Full Idea: Simplified S5 rules: a) if n ◊X then kX b) if n ¬□X then k ¬X c) if n □X then k X d) if n ¬◊X then k ¬X. 'n' picks any world; in a) and b) 'k' asserts a new world; in c) and d) 'k' refers to a known world
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.3)
Negation: if σ ¬¬X then σ X [Fitting/Mendelsohn]
     Full Idea: General tableau rule for negation: if σ ¬¬X then σ X
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
Disj: a) if σ ¬(X∨Y) then σ ¬X and σ ¬Y b) if σ X∨Y then σ X or σ Y [Fitting/Mendelsohn]
     Full Idea: General tableau rules for disjunctions: a) if σ ¬(X ∨ Y) then σ ¬X and σ ¬Y b) if σ X ∨ Y then σ X or σ Y
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
Existential: a) if σ ◊X then σ.n X b) if σ ¬□X then σ.n ¬X [n is new] [Fitting/Mendelsohn]
     Full Idea: General tableau rules for existential modality: a) if σ ◊ X then σ.n X b) if σ ¬□ X then σ.n ¬X , where n introduces some new world (rather than referring to a world that can be seen).
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
     A reaction: Note that the existential rule of ◊, usually read as 'possibly', asserts something about a new as yet unseen world, whereas □ only refers to worlds which can already be seen,
T reflexive: a) if σ □X then σ X b) if σ ¬◊X then σ ¬X [Fitting/Mendelsohn]
     Full Idea: System T reflexive rules (also for B, S4, S5): a) if σ □X then σ X b) if σ ¬◊X then σ ¬X
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.3)
D serial: a) if σ □X then σ ◊X b) if σ ¬◊X then σ ¬□X [Fitting/Mendelsohn]
     Full Idea: System D serial rules (also for T, B, S4, S5): a) if σ □X then σ ◊X b) if σ ¬◊X then σ ¬□X
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.3)
B symmetric: a) if σ.n □X then σ X b) if σ.n ¬◊X then σ ¬X [n occurs] [Fitting/Mendelsohn]
     Full Idea: System B symmetric rules (also for S5): a) if σ.n □X then σ X b) if σ.n ¬◊X then σ ¬X [where n is a world which already occurs]
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.3)
4 transitive: a) if σ □X then σ.n □X b) if σ ¬◊X then σ.n ¬◊X [n occurs] [Fitting/Mendelsohn]
     Full Idea: System 4 transitive rules (also for K4, S4, S5): a) if σ □X then σ.n □X b) if σ ¬◊X then σ.n ¬◊X [where n is a world which already occurs]
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.3)
4r rev-trans: a) if σ.n □X then σ □X b) if σ.n ¬◊X then σ ¬◊X [n occurs] [Fitting/Mendelsohn]
     Full Idea: System 4r reversed-transitive rules (also for S5): a) if σ.n □X then σ □X b) if σ.n ¬◊X then σ ¬◊X [where n is a world which already occurs]
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.3)
If a proposition is possibly true in a world, it is true in some world accessible from that world [Fitting/Mendelsohn]
     Full Idea: If a proposition is possibly true in a world, then it is also true in some world which is accessible from that world. That is: Γ ||- ◊X ↔ for some Δ ∈ G, ΓRΔ then Δ ||- X.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.6)
If a proposition is necessarily true in a world, it is true in all worlds accessible from that world [Fitting/Mendelsohn]
     Full Idea: If a proposition is necessarily true in a world, then it is also true in all worlds which are accessible from that world. That is: Γ ||- □X ↔ for every Δ ∈ G, if ΓRΔ then Δ ||- X.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.6)
Conj: a) if σ X∧Y then σ X and σ Y b) if σ ¬(X∧Y) then σ ¬X or σ ¬Y [Fitting/Mendelsohn]
     Full Idea: General tableau rules for conjunctions: a) if σ X ∧ Y then σ X and σ Y b) if σ ¬(X ∧ Y) then σ ¬X or σ ¬Y
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
Bicon: a)if σ(X↔Y) then σ(X→Y) and σ(Y→X) b) [not biconditional, one or other fails] [Fitting/Mendelsohn]
     Full Idea: General tableau rules for biconditionals: a) if σ (X ↔ Y) then σ (X → Y) and σ (Y → X) b) if σ ¬(X ↔ Y) then σ ¬(X → Y) or σ ¬(Y → X)
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
Implic: a) if σ ¬(X→Y) then σ X and σ ¬Y b) if σ X→Y then σ ¬X or σ Y [Fitting/Mendelsohn]
     Full Idea: General tableau rules for implications: a) if σ ¬(X → Y) then σ X and σ ¬Y b) if σ X → Y then σ ¬X or σ Y
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
Universal: a) if σ ¬◊X then σ.m ¬X b) if σ □X then σ.m X [m exists] [Fitting/Mendelsohn]
     Full Idea: General tableau rules for universal modality: a) if σ ¬◊ X then σ.m ¬X b) if σ □ X then σ.m X , where m refers to a world that can be seen (rather than introducing a new world).
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 2.2)
     A reaction: Note that the universal rule of □, usually read as 'necessary', only refers to worlds which can already be seen, whereas possibility (◊) asserts some thing about a new as yet unseen world.
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / b. System K
The system K has no accessibility conditions [Fitting/Mendelsohn]
     Full Idea: The system K has no frame conditions imposed on its accessibility relation.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.8)
     A reaction: The system is named K in honour of Saul Kripke.
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / c. System D
□P → P is not valid in D (Deontic Logic), since an obligatory action may be not performed [Fitting/Mendelsohn]
     Full Idea: System D is usually thought of as Deontic Logic, concerning obligations and permissions. □P → P is not valid in D, since just because an action is obligatory, it does not follow that it is performed.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.12.2 Ex)
The system D has the 'serial' conditon imposed on its accessibility relation [Fitting/Mendelsohn]
     Full Idea: The system D has the 'serial' condition imposed on its accessibility relation - that is, every world must have some world which is accessible to it.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.8)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / d. System T
The system T has the 'reflexive' conditon imposed on its accessibility relation [Fitting/Mendelsohn]
     Full Idea: The system T has the 'reflexive' condition imposed on its accessibility relation - that is, every world must be accessible to itself.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.8)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / e. System K4
The system K4 has the 'transitive' condition on its accessibility relation [Fitting/Mendelsohn]
     Full Idea: The system K4 has the 'transitive' condition imposed on its accessibility relation - that is, if a relation holds between worlds 1 and 2 and worlds 2 and 3, it must hold between worlds 1 and 3. The relation carries over.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.8)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B
The system B has the 'reflexive' and 'symmetric' conditions on its accessibility relation [Fitting/Mendelsohn]
     Full Idea: The system B has the 'reflexive' and 'symmetric' conditions imposed on its accessibility relation - that is, every world must be accessible to itself, and any relation between worlds must be mutual.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.8)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
The system S4 has the 'reflexive' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn]
     Full Idea: The system S4 has the 'reflexive' and 'transitive' conditions imposed on its accessibility relation - that is, every world is accessible to itself, and accessibility carries over a series of worlds.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.8)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
System S5 has the 'reflexive', 'symmetric' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn]
     Full Idea: The system S5 has the 'reflexive', 'symmetric' and 'transitive' conditions imposed on its accessibility relation - that is, every world is self-accessible, and accessibility is mutual, and it carries over a series of worlds.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.8)
     A reaction: S5 has total accessibility, and hence is the most powerful system (though it might be too powerful).
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
Modality affects content, because P→◊P is valid, but ◊P→P isn't [Fitting/Mendelsohn]
     Full Idea: P→◊P is usually considered to be valid, but its converse, ◊P→P is not, so (by Frege's own criterion) P and possibly-P differ in conceptual content, and there is no reason why logic should not be widened to accommodate this.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.2)
     A reaction: Frege had denied that modality affected the content of a proposition (1879:p.4). The observation here is the foundation for the need for a modal logic.
4. Formal Logic / D. Modal Logic ML / 5. Epistemic Logic
In epistemic logic knowers are logically omniscient, so they know that they know [Fitting/Mendelsohn]
     Full Idea: In epistemic logic the knower is treated as logically omniscient. This is puzzling because one then cannot know something and yet fail to know that one knows it (the Principle of Positive Introspection).
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.11)
     A reaction: This is nowadays known as the K-K Problem - to know, must you know that you know. Broadly, we find that externalists say you don't need to know that you know (so animals know things), but internalists say you do need to know that you know.
Read epistemic box as 'a knows/believes P' and diamond as 'for all a knows/believes, P' [Fitting/Mendelsohn]
     Full Idea: In epistemic logic we read Υ as 'KaP: a knows that P', and ◊ as 'PaP: it is possible, for all a knows, that P' (a is an individual). For belief we read them as 'BaP: a believes that P' and 'CaP: compatible with everything a believes that P'.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.11)
     A reaction: [scripted capitals and subscripts are involved] Hintikka 1962 is the source of this. Fitting and Mendelsohn prefer □ to read 'a is entitled to know P', rather than 'a knows that P'.
4. Formal Logic / D. Modal Logic ML / 6. Temporal Logic
F: will sometime, P: was sometime, G: will always, H: was always [Fitting/Mendelsohn]
     Full Idea: We introduce four future and past tense operators: FP: it will sometime be the case that P. PP: it was sometime the case that P. GP: it will always be the case that P. HP: it has always been the case that P. (P itself is untensed).
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.10)
     A reaction: Temporal logic begins with A.N. Prior, and starts with □ as 'always', and ◊ as 'sometimes', but then adds these past and future divisions. Two different logics emerge, taking □ and ◊ as either past or as future.
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
The Barcan says nothing comes into existence; the Converse says nothing ceases; the pair imply stability [Fitting/Mendelsohn]
     Full Idea: The Converse Barcan says nothing passes out of existence in alternative situations. The Barcan says that nothing comes into existence. The two together say the same things exist no matter what the situation.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 4.9)
     A reaction: I take the big problem to be that these reflect what it is you want to say, and that does not keep stable across a conversation, so ordinary rational discussion sometimes asserts these formulas, and 30 seconds later denies them.
The Barcan corresponds to anti-monotonicity, and the Converse to monotonicity [Fitting/Mendelsohn]
     Full Idea: The Barcan formula corresponds to anti-monotonicity, and the Converse Barcan formula corresponds to monotonicity.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 6.3)
5. Theory of Logic / F. Referring in Logic / 3. Property (λ-) Abstraction
'Predicate abstraction' abstracts predicates from formulae, giving scope for constants and functions [Fitting/Mendelsohn]
     Full Idea: 'Predicate abstraction' is a key idea. It is a syntactic mechanism for abstracting a predicate from a formula, providing a scoping mechanism for constants and function symbols similar to that provided for variables by quantifiers.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], Pref)
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
The Indiscernibility of Identicals has been a big problem for modal logic [Fitting/Mendelsohn]
     Full Idea: Equality has caused much grief for modal logic. Many of the problems, which have struck at the heart of the coherence of modal logic, stem from the apparent violations of the Indiscernibility of Identicals.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 7.1)
     A reaction: Thus when I say 'I might have been three inches taller', presumably I am referring to someone who is 'identical' to me, but who lacks one of my properties. A simple solution is to say that the person is 'essentially' identical.
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
□ must be sensitive as to whether it picks out an object by essential or by contingent properties [Fitting/Mendelsohn]
     Full Idea: If □ is to be sensitive to the quality of the truth of a proposition in its scope, then it must be sensitive as to whether an object is picked out by an essential property or by a contingent one.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 4.3)
     A reaction: This incredibly simple idea strikes me as being powerful and important. ...However, creating illustrative examples leaves me in a state of confusion. You try it. They cite '9' and 'number of planets'. But is it just nominal essence? '9' must be 9.
Objects retain their possible properties across worlds, so a bundle theory of them seems best [Fitting/Mendelsohn]
     Full Idea: The property of 'possibly being a Republican' is as much a property of Bill Clinton as is 'being a democrat'. So we don't peel off his properties from world to world. Hence the bundle theory fits our treatment of objects better than bare particulars.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 7.3)
     A reaction: This bundle theory is better described in recent parlance as the 'modal profile'. I am reluctant to talk of a modal truth about something as one of its 'properties'. An objects, then, is a bundle of truths?
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Counterpart relations are neither symmetric nor transitive, so there is no logic of equality for them [Fitting/Mendelsohn]
     Full Idea: The main technical problem with counterpart theory is that the being-a-counterpart relation is, in general, neither symmetric nor transitive, so no natural logic of equality is forthcoming.
     From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 4.5)
     A reaction: That is, nothing is equal to a counterpart, either directly or indirectly.
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / b. Transcendental idealism
Appearances are nothing beyond representations, which is transcendental ideality [Moore,AW]
     Full Idea: Appearances in general are nothing outside our representations, which is just what we mean by transcendental ideality.
     From: A.W. Moore (The Evolution of Modern Metaphysics [2012], B535/A507)
14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
To the four causes Plato adds a fifth, the idea which guided the event [Seneca]
     Full Idea: To the four Aristotelian causes Plato adds a fifth in the model - what he himself calls the 'idea' - this being what the sculptor had constantly before his eyes as he executed the intended work.
     From: Seneca the Younger (Letters from a Stoic [c.60], 065)
     A reaction: A very interesting interpretation. I take the four 'causes' to be primarily the four 'explanations', and it exactly fits how we should understand Plato, as offer a crucial underlying explanation. The statue is Aristotle's example.
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
If everything can be measured, try measuring the size of a man's soul [Seneca]
     Full Idea: Nothing's outside your scope when it comes to measurement. Well, if you're such an expert, measure a man's soul; tell me how large or how small that is.
     From: Seneca the Younger (Letters from a Stoic [c.60], 088)
     A reaction: This is Descartes's non-spatial argument, which I take to be one of the four main props to his mind-body dualism. As always, it is expressed with beautiful concision by Seneca.
19. Language / B. Reference / 1. Reference theories
Referring to a person, and speaking about him, are very different [Seneca]
     Full Idea: It makes a very great difference whether you refer to the person directly, or speak about him.
     From: Seneca the Younger (Letters from a Stoic [c.60], 117.13), quoted by A.A. Long - Hellenistic Philosophy 4.3.2
     A reaction: We seem to think that the distinctiveness of reference was first spotted by Frege. Not so.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
Trouble in life comes from copying other people, which is following convention instead of reason [Seneca]
     Full Idea: One of the causes of the troubles that beset us is the way our lives are guided by the example of others; instead of being set to rights by reason we're seduced by convention.
     From: Seneca the Younger (Letters from a Stoic [c.60], 123)
     A reaction: An interesting practical spin and critique of the standard metaethical idea that morality is just convention. If you think morality is convention, presumably your moral duty is to imitate your neighbours. Nice deconstruction.
22. Metaethics / B. Value / 2. Values / d. Health
Humans acquired the concept of virtue from an analogy with bodily health and strength [Seneca, by Allen]
     Full Idea: Seneca held that human beings owe the original acquisition of the concept of virtue to an analogy with bodily health and strength
     From: report of Seneca the Younger (Letters from a Stoic [c.60], 120.5) by James Allen - Soul's Virtue and the Health of the Body p.76
     A reaction: This is an unusual view, even for a stoic, but shows how close the concepts of health and virtue were. Notice that it is strength as well as health. Plato just emphasises mental and physical harmony.
22. Metaethics / B. Value / 2. Values / e. Death
We know death, which is like before birth; ceasing to be and never beginning are the same [Seneca]
     Full Idea: I already know what death is like - it will be the same after me as it was before me. ..Only an utter idiot would think a lamp was worse off when it was put out than before it was lit. ..What does it matter whether you cease to be or never begin?
     From: Seneca the Younger (Letters from a Stoic [c.60], 054)
     A reaction: These sentiments are, interestingly, derived from the epicureans, rather than from the stoic tradition, but to us they probably look close together, where they looked like opponents at the time.
Living is nothing wonderful; what matters is to die well [Seneca]
     Full Idea: There's nothing so very great about living - all your slaves and all the animals do it. What is, however, a great thing is to die in a manner which is honourable, enlightened and courageous.
     From: Seneca the Younger (Letters from a Stoic [c.60], 077)
     A reaction: You get the feeling that Seneca actually thought suicide was better than a natural death. Did he actually seek his own death? It is an odd interpretation of his own stoic injunction to 'live according to nature'.
It is as silly to lament ceasing to be as to lament not having lived in the remote past [Seneca]
     Full Idea: Wouldn't you think a man a prize fool if he burst into tears because he didn't live a thousand years ago? A man is such a fool for shedding tears because he isn't going to be alive a thousand years from now.
     From: Seneca the Younger (Letters from a Stoic [c.60], 077)
     A reaction: These thoughts are traditional, dating back to Epicurus, but Seneca is exceptionally going at finding new variations and examples to reinforce the basic thought.
22. Metaethics / B. Value / 2. Values / g. Love
Is anything sweeter than valuing yourself more when you find you are loved? [Seneca]
     Full Idea: Can anything be sweeter than to find that you are so dear to your wife that this makes you dearer to yourself?
     From: Seneca the Younger (Letters from a Stoic [c.60], 104)
     A reaction: Another lovely penetrating remark from Seneca. I suppose a symptom of low self-esteem might be 'why does she love someone as worthless as me?', but that would be unusual.
22. Metaethics / B. Value / 2. Values / i. Self-interest
Selfishness does not produce happiness; to live for yourself, live for others [Seneca]
     Full Idea: No one can lead a happy life if he thinks only of himself and turns everything to his own purposes. You should live for the other person if you wish to live for yourself.
     From: Seneca the Younger (Letters from a Stoic [c.60], 048)
     A reaction: It is important to see this as a key aspect of the ancient aspiration to virtue. The end result is not far from Christianity. It is simplistic to see the quest for virtue as a crass self-obsessed quest for self-improvement. We are social.
22. Metaethics / C. The Good / 2. Happiness / a. Nature of happiness
A man is as unhappy as he has convinced himself he is [Seneca]
     Full Idea: A man is as unhappy as he has convinced himself he is.
     From: Seneca the Younger (Letters from a Stoic [c.60], 078)
     A reaction: Seneca is a very penetrating thinker about ordinary life - an aspect of philosophy which is nowadays totally neglected by the most eminent philosophers.
22. Metaethics / C. The Good / 2. Happiness / b. Eudaimonia
Life is like a play - it is the quality that matters, not the length [Seneca]
     Full Idea: As it is with a play, so it is with life - what matters is not how long the acting lasts, but how good it is.
     From: Seneca the Younger (Letters from a Stoic [c.60], 077)
     A reaction: A very nice epigram, culminating the wonderful Letter 77 on the subject of death. A play needs to be a decent length if it is to exhibit its qualities. It would be heartbreaking if all of Shakespeare's plays were just 20-minute sketches.
22. Metaethics / C. The Good / 3. Pleasure / e. Role of pleasure
We are scared of death - except when we are immersed in pleasure! [Seneca]
     Full Idea: You are scared of death - but how heedless of it you are while you are dealing with a dish of choice mushrooms!
     From: Seneca the Younger (Letters from a Stoic [c.60], 077)
     A reaction: A beautifully simple observation, from the greatest philosopher of death. Maybe hospices should concentrate on sex, drugs and rock and roll.
22. Metaethics / C. The Good / 3. Pleasure / f. Dangers of pleasure
The whole point of pleasure-seeking is novelty, and abandoning established ways [Seneca]
     Full Idea: The whole object of luxurious living is the delight it takes in irregular ways and in not merely departing from the correct course but going to the farthest point away from it, and in eventually even taking a stand diametrically opposed to it.
     From: Seneca the Younger (Letters from a Stoic [c.60], 122)
     A reaction: A rather conservative and puritanical remark, but worthy of contemplation even for committed hedonists. It is just a sad facts that most pleasures diminish with familiarity. Small children make delightful remarks. Imagine if they repeated them.
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / b. Living naturally
Nature doesn't give us virtue; we must unremittingly pursue it, as a training and an art [Seneca]
     Full Idea: Nature does not give a man virtue; the process of becoming a good man is an art. ...Virtue only comes to a character which has been thoroughly schooled and trained and brought to a pitch of perfection by unremitting practice.
     From: Seneca the Younger (Letters from a Stoic [c.60], 090)
     A reaction: This is an important gloss from a leading stoic on the slogan of 'live according to nature'. One might say that the natural life must be 'tracked' (as Philip Larkin says we track happiness). The natural life is, above all, the rational life, for stoics.
Living contrary to nature is like rowing against the stream [Seneca]
     Full Idea: For those who follow nature everything is easy and straightforward, whereas for those who fight against her life is just like rowing against the stream.
     From: Seneca the Younger (Letters from a Stoic [c.60], 102)
     A reaction: A classic statement of the well-known stoic slogan, but expressed with Seneca's characteristic elegance. There is always a slight hidden of dubious fatalism in the slogan. 'Rage, rage, against the dying of the light!' - Dylan Thomas.
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / e. Character
Character is ruined by not looking back over our pasts, since the future rests on the past [Seneca]
     Full Idea: What really ruins our characters is the fact that none of us looks back over his life. We think a little about what we are going to do, and fail to think about what we have done, yet plans for the future depend on the past.
     From: Seneca the Younger (Letters from a Stoic [c.60], 083)
     A reaction: One always assumes that writings about the wisdom of daily life will be one mass of clichés, but Seneca proves otherwise. With a pang I realise that I may be too guilty of not thinking about the past. I've even been proud of it.
23. Ethics / C. Virtue Theory / 3. Virtues / b. Temperance
It's no good winning lots of fights, if you are then conquered by your own temper [Seneca]
     Full Idea: What's the use of overcoming opponent after opponent in the wrestling or boxing rings if you can be overcome by your temper?
     From: Seneca the Younger (Letters from a Stoic [c.60], 088)
     A reaction: He has such a nice way of presenting what might be traditional and commonplace ideas. If you see life as a battle, then you should think very carefully about who the opponents are - because they may be hiding within.
Excessive curiosity is a form of intemperance [Seneca]
     Full Idea: To want to know more than is sufficient is a form of intemperance.
     From: Seneca the Younger (Letters from a Stoic [c.60], 088)
     A reaction: This comes as a bit of a surprise, given the high value that philosophers place on knowledge. I'm reminded of Auberon Waugh's criticism of the Scots as a 'wildly over-educated people'. I think the problem is what you could have been doing instead.
24. Political Theory / B. Nature of a State / 2. State Legitimacy / d. General will
To govern used to mean to serve, not to rule; rulers did not test their powers over those who bestowed it [Seneca]
     Full Idea: In the Golden Age, to govern was to serve, not to rule. No one used to try out the extent of his power over those to whom he owed that power in the first place.
     From: Seneca the Younger (Letters from a Stoic [c.60], 090)
     A reaction: I spent my professional career trying to persuade people that management should be a subjection to the managed. Wake up! The second half of this idea is the interesting bit - the temptation to just 'try out' your powers gets to them all.
25. Social Practice / E. Policies / 5. Education / c. Teaching
One joy of learning is making teaching possible [Seneca]
     Full Idea: Part of my joy in learning is that it puts me in a position to teach.
     From: Seneca the Younger (Letters from a Stoic [c.60], 006)
     A reaction: This doesn't quite distinguish between bad learning and good learning, but I take a commitment to wanting to teach what you know as an essential part of wanting to know.
Both teachers and pupils should aim at one thing - the improvement of the pupil [Seneca]
     Full Idea: A person teaching and a person learning should have the same end in view: the improvement of the latter.
     From: Seneca the Younger (Letters from a Stoic [c.60], 108)
     A reaction: [He cites a philospher called Attalus for this remark] This is worthy to be up in the hall of every educational institution in the world, and especially in the staff rooms.
25. Social Practice / F. Life Issues / 4. Suicide
Suicide may be appropriate even when it is not urgent, if there are few reasons against it [Seneca]
     Full Idea: There are many occasions on which a man should leave life not only bravely but for reasons which are not as pressing as they might be - the reasons which restrain us being not so pressing either.
     From: Seneca the Younger (Letters from a Stoic [c.60], 077)
     A reaction: This is an interesting and startling claim from the great champion of suicide, who nobly and memorably committed suicide himself. But we all dread a loved one miscalculating Seneca's dialectic, and dying when living would have been better.
If we control our own death, no one has power over us [Seneca]
     Full Idea: No one has power over us when death is in our own power.
     From: Seneca the Younger (Letters from a Stoic [c.60], 091)
     A reaction: A classic slogan for the stoic view of suicide, an idea that crops up in Shakespeare's 'Julius Caesar'. He doesn't seem to have understood that they can take away your shoelaces.
Sometimes we have a duty not to commit suicide, for those we love [Seneca]
     Full Idea: There are times when, however pressing one's reasons to the contrary, one's dying breath must be held back as it is passing one's lips, even if this is torture, simply out of consideration for one's dear ones.
     From: Seneca the Younger (Letters from a Stoic [c.60], 104)
     A reaction: This is, of course, a highly significant counterbalance to his normal acceptance of suicide. I wish anyone who is planning suicide would heed it. They have no idea how much suffering will usually result from their action.
27. Natural Reality / D. Time / 1. Nature of Time / a. Absolute time
Does time exist on its own? Did anything precede it? Did it pre-exist the cosmos? [Seneca]
     Full Idea: Look how many questions there are on time. Does it have an existence of its own? Does anything exist prior to time, independently of it? Did it begin with the universe, or did it exist even before then?
     From: Seneca the Younger (Letters from a Stoic [c.60], 088)
     A reaction: I'm not sure that the questions have shifted or become any clearer after two thousand years, despite Einstein and co. Note that discussions of time were not initiated by Augustine.