Combining Philosophers

All the ideas for M Fitting/R Mendelsohn, Anon (Upan) and Jason Crease

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63 ideas

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
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.
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)
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.
16. Persons / A. Concept of a Person / 3. Persons as Reasoners
Self is the rider, intellect the charioteer, mind the reins, and body the chariot [Anon (Upan)]
     Full Idea: Know that the Self (Atman) is the rider, and the body the chariot; that the intellect is the charioteer, and the mind the reins.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Katha')
     A reaction: This strikes me as exactly right. Even my intellectual powers are servants of the self. This suggests the view of the mind as a tool, which does not seem to occur in modern discussions.
16. Persons / C. Self-Awareness / 2. Knowing the Self
We have an apparent and a true self; only the second one exists, and we must seek to know it [Anon (Upan)]
     Full Idea: There are two selves, the apparent self, and the real Self. Of these it is the real Self (Atman), and he alone, who must be felt as truly existing. To the man who has felt him as truly existing he reveals his innermost nature.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Katha')
     A reaction: A central Hindu doctrine against which Buddhism rebelled, by denying the self altogether. I prefer the Hindu view. A desire to abandon the self just seems to be a desire for death. Knowledge of our essential self is more interesting. But see Idea 2932!
17. Mind and Body / A. Mind-Body Dualism / 5. Parallelism
If parallelism is true, how does the mind know about the body? [Crease]
     Full Idea: In parallelism, the idea that we have a body is like an astronaut hearing shouting on the moon, and reasoning that as this is impossible he must be simultaneously imagining shouting AND there is real shouting taking place!
     From: Jason Crease (works [2001]), quoted by PG - Db (ideas)
     A reaction: This seems to capture the absurdity of Leibniz's proposal. I experience what my brain is doing, but not because my brain is doing it. I would never know if God had made a slight error in setting His two 'clocks'; their accuracy is just a pious hope.
18. Thought / D. Concepts / 5. Concepts and Language / a. Concepts and language
Without speech we cannot know right/wrong, true/false, good/bad, or pleasant/unpleasant [Anon (Upan)]
     Full Idea: If there were no speech, neither right nor wrong would be known, neither the true nor the false, neither the good nor the bad, neither the pleasant nor the unpleasant.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Chandogya')
     A reaction: This could stand as the epigraph for the whole of modern philosophy of language. However, the text goes on to say that mind is higher than speech. The test question is the mental capabilities of animals. Do they 'know' pleasure, or truth?
22. Metaethics / C. The Good / 3. Pleasure / c. Value of pleasure
The wise prefer good to pleasure; the foolish are drawn to pleasure by desire [Anon (Upan)]
     Full Idea: The wise prefer the good to the pleasant; the foolish, driven by fleshly desires, prefer the pleasant ot the good.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Katha')
     A reaction: If you consider appropriate diet, this is too obvious to be worth saying. The complication is that it is doubtful whether a life without pleasure is wholly good, and even the pleasure of food is not bad. Of two good foods, prefer the pleasant one.
25. Social Practice / E. Policies / 5. Education / c. Teaching
Let your teacher be a god to you [Anon (Upan)]
     Full Idea: Let your teacher be a god to you.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Taittiriya')
     A reaction: Yes indeed. The problem in the west is that we are committed to encouraging a critical and questioning attitude. A high value for knowledge must precede a high value for a teacher.
26. Natural Theory / B. Natural Kinds / 2. Defining Kinds
By knowing one piece of clay or gold, you know all of clay or gold [Anon (Upan)]
     Full Idea: By knowing one lump of clay, all things made of clay are known; by knowing a nugget of gold, all things made of gold are known.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Chandogya')
     A reaction: I can't think of a better basic definition of a natural kind. There is an inductive assumption, of course, which hits trouble when you meet fool's gold, or two different sorts of jade. But the concept of a natural kind is no more than this.
27. Natural Reality / E. Cosmology / 2. Eternal Universe
Originally there must have been just Existence, which could not come from non-existence [Anon (Upan)]
     Full Idea: In the beginning there was Existence, One only, without a second. Some say that in the beginning there was non-existence only, and that out of that the universe was born. But how could such a thing be? How could existence be born of non-existence?
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Chandogya')
     A reaction: A very rare instance of an argument in the Upanishads, arising out of a disagreement. The monotheistic religions have preferred to make God the eternal element, presumably because that raises his status, but is also explains the start as a decision.
28. God / A. Divine Nature / 1. God
Brahma, supreme god and protector of the universe, arose from the ocean of existence [Anon (Upan)]
     Full Idea: Out of the infinite ocean of existence arose Brahma, first-born and foremost among the gods. From him sprang the universe, and he became its protector.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Mundaka')
     A reaction: Brahma does not have eternal (or necessary) existence. Could Brahma cease to exist? I suppose we cannot ask what caused the appearance of Brahma? Is it part of a plan, or just luck, or some sort of necessity?
28. God / B. Proving God / 3. Proofs of Evidence / a. Cosmological Proof
Brahman is the Uncaused Cause [Anon (Upan)]
     Full Idea: Brahman is the Uncaused Cause.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Katha')
     A reaction: This precedes Aquinas (Idea 1430) by over two thousand years. The theological trick is to admit one Uncaused Cause, but somehow exclude further instances, such as my bicycle getting a puncture. Does this undermine the Principle of Sufficient Reason?
28. God / C. Attitudes to God / 2. Pantheism
Earth, food, fire, sun are all forms of Brahman [Anon (Upan)]
     Full Idea: Earth, food, fire, sun - all these that you worship - are forms of Brahman.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Chandogya')
     A reaction: In 'Taittiriya' food is named as the "chief of all things". Pantheism seems to arise from a desire that one's god should have every conceivable good, so in addition to power and knowledge, your god must keep you warm and healthy.
29. Religion / A. Polytheistic Religion / 3. Hinduism
The gods are not worshipped for their own sake, but for the sake of the Self [Anon (Upan)]
     Full Idea: It is not for the sake of the gods, my beloved, that the gods are worshipped, but for the sake of the Self (Atman).
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Brihadaranyaka')
     A reaction: There is an uneasy selfish streak in all religions, which conflicts with their exhorations to altruism, and to the love of the gods. It also occurs in the exhortation of Socrates to be virtuous. 'Pure' altruism seems only to arise in the 18th century.
A man with desires is continually reborn, until his desires are stilled [Anon (Upan)]
     Full Idea: A man acts according to desires; after death he reaps the harvest of his deeds, and returns again to the world of action. Thus he who has desires continues subject to rebirth, but he in who desire is stilled suffers no rebirth.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Brihadaranyaka')
     A reaction: I greatly prefer the Stoic idea (Idea 3066) that we should live according to nature, to this perverse longing to completely destroy our own nature and become something we are not. Play the cards you are dealt, which include desires.
Damayata - be self-controlled! Datta - be charitable! Dayadhwam - be compassionate! [Anon (Upan)]
     Full Idea: The storm-clouds thunder: Da! Da! Da! Damayata - be self-controlled! Datta - be charitable! Dayadhwam - be compassionate!
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Brihadaranyaka')
     A reaction: Compassion seems to imply charity, so it comes down to 'Be self-controlled and compassionate'. Only the wildest romantic could be against self-control. Only Nietzsche could be against compassion (Idea 4425).
Those ignorant of Atman return as animals or plants, according to their merits [Anon (Upan)]
     Full Idea: Of those ignorant of the Self (Atman), some enter into beings possessed of wombs, others enter into plants - according to their deeds and the growth of their intelligence.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Katha')
     A reaction: "I sigh and sigh, and wish I were a tree" wrote George Herbert. You probably need the snobbery of the Indian caste system to appreciate the horrors of low rebirth. I quite fancy being a dolphin, but a tulip would be all right.
29. Religion / D. Religious Issues / 1. Religious Commitment / a. Religious Belief
Charity and ritual observance distract from the highest good of religion [Anon (Upan)]
     Full Idea: Considering religion to be observance of rituals and performance of acts of charity, the deluded remain ignorant of the highest good.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Mundaka')
     A reaction: An important reminder. In all the great religious texts the exhortation to love and charity is a minor aspect. The point is to live on a spiritual plain, attempting to relate the world of God/the gods. Daily life is either secondary or irrelevant.
29. Religion / D. Religious Issues / 1. Religious Commitment / e. Fideism
Do not seek to know Brahman by arguments, for arguments are idle and vain [Anon (Upan)]
     Full Idea: Do not seek to know Brahman by arguments, for arguments are idle and vain.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Brihadaranyaka')
     A reaction: In the end all the religions seem to gravitate towards fideism and away from reasoned argument. The Catholic Church may be the last bastion of rational theology. Islam (10th cent), Protestantism (16th) and Judaism (17th) all rejected philosophy.
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
The immortal in us is the part that never sleeps, and shapes our dreams [Anon (Upan)]
     Full Idea: That which is awake in us even while we sleep, shaping in dream the objects of our desire - that indeed is pure, that is Brahman, and that verily is called the Immortal.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Katha')
     A reaction: That is a more helpful view of what the soul might be than anything found in Christian theology. It makes it the essence of the everyday Self. It is left with the difficulty of lacking individuality, and being of limited interest to my wider Self.
The immortal Self and the sad individual self are like two golden birds perched on one tree [Anon (Upan)]
     Full Idea: Like two birds of golden plumage, the individual self and the immortal Self perch on the branches of the same tree. The individual self, deluded by forgetfulness of his identity with the divine self, bewildered by his ego, grieves and is sad.
     From: Anon (Upan) (The Upanishads [c.950 BCE], 'Mundaka')
     A reaction: Hinduism gives a much clearer and bolder picture of the soul than Christianity does. I don't see much consolation in the immortality of the wonderful Self, if my individual self is doomed to misery and extinction. Which one is me?