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All the ideas for 'What is Logic?st1=Ian Hacking', 'Twilight of the Idols' and 'Introduction to the Theory of Logic'

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78 ideas

1. Philosophy / B. History of Ideas / 4. Early European Thought
Judging by the positive forces, the Renaissance was the last great age [Nietzsche]
     Full Idea: Ages are to be assessed by their positive forces - and by this assessment the age of the Renaissance, so prodigal and so fateful, appears as the last great age.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.37)
     A reaction: I suspect that Nietzsche places art very high among the positive forces. Science and technology showed barely a glimmer during the Renaissance. Mathematics moved very little, Copernicus was ignored, and logic was static.
1. Philosophy / C. History of Philosophy / 2. Ancient Philosophy / b. Pre-Socratic philosophy
I revere Heraclitus [Nietzsche]
     Full Idea: I set apart with high reverence the name of Heraclitus.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.2)
1. Philosophy / C. History of Philosophy / 2. Ancient Philosophy / c. Classical philosophy
Thucydides was the perfect anti-platonist sophist [Nietzsche]
     Full Idea: My recreation, my preference, my cure from all Platonism has always been Thucydides. …Sophist culture, by which I mean realist culture, attains in him its perfect expression.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 9.2)
1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Thinking has to be learned in the way dancing has to be learned [Nietzsche]
     Full Idea: Thinking has to be learned in the way dancing has to be learned.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 7.7)
     A reaction: Nice. At its deepest level thinking isn't a rational process?
1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
Wanting a system in philosophy is a lack of integrity [Nietzsche]
     Full Idea: I mistrust all systematizers and avoid them. The will to system is a lack of integrity.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], Maxim 26)
2. Reason / A. Nature of Reason / 7. Status of Reason
I want to understand the Socratic idea that 'reason equals virtue equals happiness' [Nietzsche]
     Full Idea: I seek to understand out of what idiosyncrasy that Socratic equation 'reason equals virtue equals happiness' derives.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.04)
2. Reason / C. Styles of Reason / 1. Dialectic
With dialectics the rabble gets on top [Nietzsche]
     Full Idea: With dialectics the rabble gets on top.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.05)
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
     Full Idea: Today we expect that anything worth calling a definition should imply a semantics.
     From: Ian Hacking (What is Logic? [1979], §10)
     A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives.
2. Reason / E. Argument / 6. Conclusive Proof
Anything which must first be proved is of little value [Nietzsche]
     Full Idea: What has first to have itself proved is of little value.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.05)
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
     Full Idea: 'Dilution' (or 'Thinning') provides an essential contrast between deductive and inductive reasoning; for the introduction of new premises may spoil an inductive inference.
     From: Ian Hacking (What is Logic? [1979], §06.2)
     A reaction: That is, inductive logic (if there is such a thing) is clearly non-monotonic, whereas classical inductive logic is monotonic.
Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
     Full Idea: If A |- B and B |- C, then A |- C. This generalises to: If Γ|-A,Θ and Γ,A |- Θ, then Γ |- Θ. Gentzen called this 'cut'. It is the transitivity of a deduction.
     From: Ian Hacking (What is Logic? [1979], §06.3)
     A reaction: I read the generalisation as 'If A can be either a premise or a conclusion, you can bypass it'. The first version is just transitivity (which by-passes the middle step).
Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
     Full Idea: Only the cut rule can have a conclusion that is less complex than its premises. Hence when cut is not used, a derivation is quite literally constructive, building up from components. Any theorem obtained by cut can be obtained without it.
     From: Ian Hacking (What is Logic? [1979], §08)
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Sets can be defined by 'enumeration', or by 'abstraction' (based on a property) [Zalabardo]
     Full Idea: We can define a set by 'enumeration' (by listing the items, within curly brackets), or by 'abstraction' (by specifying the elements as instances of a property), pretending that they form a determinate totality. The latter is written {x | x is P}.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §1.3)
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
The 'Cartesian Product' of two sets relates them by pairing every element with every element [Zalabardo]
     Full Idea: The 'Cartesian Product' of two sets, written A x B, is the relation which pairs every element of A with every element of B. So A x B = { | x ∈ A and y ∈ B}.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §1.6)
A 'partial ordering' is reflexive, antisymmetric and transitive [Zalabardo]
     Full Idea: A binary relation in a set is a 'partial ordering' just in case it is reflexive, antisymmetric and transitive.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §1.6)
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Determinacy: an object is either in a set, or it isn't [Zalabardo]
     Full Idea: Principle of Determinacy: For every object a and every set S, either a is an element of S or a is not an element of S.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §1.2)
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / l. Axiom of Specification
Specification: Determinate totals of objects always make a set [Zalabardo]
     Full Idea: Principle of Specification: Whenever we can specify a determinate totality of objects, we shall say that there is a set whose elements are precisely the objects that we have specified.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §1.3)
     A reaction: Compare the Axiom of Specification. Zalabardo says we may wish to consider sets of which we cannot specify the members.
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
The various logics are abstractions made from terms like 'if...then' in English [Hacking]
     Full Idea: I don't believe English is by nature classical or intuitionistic etc. These are abstractions made by logicians. Logicians attend to numerous different objects that might be served by 'If...then', like material conditional, strict or relevant implication.
     From: Ian Hacking (What is Logic? [1979], §15)
     A reaction: The idea that they are 'abstractions' is close to my heart. Abstractions from what? Surely 'if...then' has a standard character when employed in normal conversation?
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
     Full Idea: First-order logic is the strongest complete compact theory with a Löwenheim-Skolem theorem.
     From: Ian Hacking (What is Logic? [1979], §13)
A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking]
     Full Idea: Henkin proved that there is no first-order treatment of branching quantifiers, which do not seem to involve any idea that is fundamentally different from ordinary quantification.
     From: Ian Hacking (What is Logic? [1979], §13)
     A reaction: See Hacking for an example of branching quantifiers. Hacking is impressed by this as a real limitation of the first-order logic which he generally favours.
A first-order 'sentence' is a formula with no free variables [Zalabardo]
     Full Idea: A formula of a first-order language is a 'sentence' just in case it has no free variables.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §3.2)
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order completeness seems to need intensional entities and possible worlds [Hacking]
     Full Idea: Second-order logic has no chance of a completeness theorem unless one ventures into intensional entities and possible worlds.
     From: Ian Hacking (What is Logic? [1979], §13)
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
Γ |= φ for sentences if φ is true when all of Γ is true [Zalabardo]
     Full Idea: A propositional logic sentence is a 'logical consequence' of a set of sentences (written Γ |= φ) if for every admissible truth-assignment all the sentences in the set Γ are true, then φ is true.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.4)
     A reaction: The definition is similar for predicate logic.
Γ |= φ if φ is true when all of Γ is true, for all structures and interpretations [Zalabardo]
     Full Idea: A formula is the 'logical consequence' of a set of formulas (Γ |= φ) if for every structure in the language and every variable interpretation of the structure, if all the formulas within the set are true and the formula itself is true.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §3.5)
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking]
     Full Idea: My doctrine is that the peculiarity of the logical constants resides precisely in that given a certain pure notion of truth and consequence, all the desirable semantic properties of the constants are determined by their syntactic properties.
     From: Ian Hacking (What is Logic? [1979], §09)
     A reaction: He opposes this to Peacocke 1976, who claims that the logical connectives are essentially semantic in character, concerned with the preservation of truth.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / b. Basic connectives
Propositional logic just needs ¬, and one of ∧, ∨ and → [Zalabardo]
     Full Idea: In propositional logic, any set containing ¬ and at least one of ∧, ∨ and → is expressively complete.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.8)
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking]
     Full Idea: For some purposes the variables of first-order logic can be regarded as prepositions and place-holders that could in principle be dispensed with, say by a system of arrows indicating what places fall in the scope of which quantifier.
     From: Ian Hacking (What is Logic? [1979], §11)
     A reaction: I tend to think of variables as either pronouns, or as definite descriptions, or as temporary names, but not as prepositions. Must address this new idea...
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
The semantics shows how truth values depend on instantiations of properties and relations [Zalabardo]
     Full Idea: The semantic pattern of a first-order language is the ways in which truth values depend on which individuals instantiate the properties and relations which figure in them. ..So we pair a truth value with each combination of individuals, sets etc.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §3.3)
     A reaction: So truth reduces to a combination of 'instantiations', which is rather like 'satisfaction'.
We can do semantics by looking at given propositions, or by building new ones [Zalabardo]
     Full Idea: We can look at semantics from the point of view of how truth values are determined by instantiations of properties and relations, or by asking how we can build, using the resources of the language, a proposition corresponding to a given semantic pattern.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §3.6)
     A reaction: The second version of semantics is model theory.
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
We make a truth assignment to T and F, which may be true and false, but merely differ from one another [Zalabardo]
     Full Idea: A truth assignment is a function from propositions to the set {T,F}. We will think of T and F as the truth values true and false, but for our purposes all we need to assume about the identity of these objects is that they are different from each other.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.4)
     A reaction: Note that T and F are 'objects'. This remark is important in understanding modern logical semantics. T and F can be equated to 1 and 0 in the language of a computer. They just mean as much as you want them to mean.
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
'Logically true' (|= φ) is true for every truth-assignment [Zalabardo]
     Full Idea: A propositional logic sentence is 'logically true', written |= φ, if it is true for every admissible truth-assignment.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.4)
Logically true sentences are true in all structures [Zalabardo]
     Full Idea: In first-order languages, logically true sentences are true in all structures.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §3.5)
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
A sentence-set is 'satisfiable' if at least one truth-assignment makes them all true [Zalabardo]
     Full Idea: A propositional logic set of sentences Γ is 'satisfiable' if there is at least one admissible truth-assignment that makes all of its sentences true.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.4)
Some formulas are 'satisfiable' if there is a structure and interpretation that makes them true [Zalabardo]
     Full Idea: A set of formulas of a first-order language is 'satisfiable' if there is a structure and a variable interpretation in that structure such that all the formulas of the set are true.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §3.5)
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A structure models a sentence if it is true in the model, and a set of sentences if they are all true in the model [Zalabardo]
     Full Idea: A structure is a model of a sentence if the sentence is true in the model; a structure is a model of a set of sentences if they are all true in the structure.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §3.6)
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
     Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic.
     From: Ian Hacking (What is Logic? [1979], §13)
     A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
If a set is defined by induction, then proof by induction can be applied to it [Zalabardo]
     Full Idea: Defining a set by induction enables us to use the method of proof by induction to establish that all the elements of the set have a certain property.
     From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.3)
7. Existence / A. Nature of Existence / 3. Being / e. Being and nothing
The 'real being' of things is a nothingness constructed from contradictions in the actual world [Nietzsche]
     Full Idea: The characteristics which have been assigned to the 'real being' of things are the characteristics of non-being, of nothingness - the 'real world has been constructed out of the contradiction of the actual world.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.6)
     A reaction: I take this to be a critique of Hegel, in particular. Could we describe the metaphysics of Nietzsche as 'constructivist'? I certainly think he is underrated as a metaphysician, because the ideas are so fragmentary.
7. Existence / A. Nature of Existence / 3. Being / h. Dasein (being human)
We get the concept of 'being' from the concept of the 'ego' [Nietzsche]
     Full Idea: Being is everywhere thought in, foisted on, as cause; it is only from the conception 'ego' that there follows, derivatively, the concept 'being'.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.5)
     A reaction: 'Being' is such a remote abstraction that I doubt whether we can say anything at all meaningful about where it 'comes from'.
7. Existence / D. Theories of Reality / 4. Anti-realism
The grounds for an assertion that the world is only apparent actually establish its reality [Nietzsche]
     Full Idea: The grounds upon which 'this' world has been designated as apparent establish rather its reality - another kind of reality is absolutely undemonstrable.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.6)
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
In language we treat 'ego' as a substance, and it is thus that we create the concept 'thing' [Nietzsche]
     Full Idea: It is the metaphysics of language (that is, of reason) ....which believes in the 'ego', in the ego as being, in the ego as substance, and which projects its belief in the ego-substance on to all things - only thus does it create the concept 'thing'.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.5)
12. Knowledge Sources / B. Perception / 6. Inference in Perception
The evidence of the senses is falsified by reason [Nietzsche]
     Full Idea: 'Reason' is the cause of our falsification of the evidence of the senses.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.1)
     A reaction: One for McDowell.
14. Science / D. Explanation / 4. Explanation Doubts / b. Rejecting explanation
Any explanation will be accepted as true if it gives pleasure and a feeling of power [Nietzsche]
     Full Idea: To trace something unknown back to something known is alleviating, soothing, gratifying and gives moreover a feeling of power. ...First principle: any explanation is better than none. ...Proof by pleasure ('by potency') as criterion of truth.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 5.5)
     A reaction: By 'proof by pleasure' he means that we find an explanation so satisfying that we cling to it. I assume it is a criterion of rationality (an epistemic virtue) to reject the principle 'any explanation is better than none'. Negative capability.
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
The 'highest' concepts are the most general and empty concepts [Nietzsche]
     Full Idea: The 'highest concepts' ...are the most general, the emptiest concepts, the last fumes of evaporating reality.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.4)
     A reaction: This could be seen as an attack on the aspirations of all of philosophy, which seeks general truths out of the chaos of experience. Should we shut up, then, and just be and do?
16. Persons / E. Rejecting the Self / 2. Self as Social Construct
There are no 'individual' persons; we are each the sum of humanity up to this moment [Nietzsche]
     Full Idea: The 'individual' ...is an error: he does not constitute a separate entity, an atom, a 'link in the chain', something merely inherited from the past - he constitutes the entire single line 'man' up to and including himself.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.33)
     A reaction: I'm not sure I understand this, but you can sort of imagine yourself as a culmination of something, rather than as an isolated entity. I'm not sure how that is supposed to affect my behaviour.
18. Thought / A. Modes of Thought / 5. Rationality / b. Human rationality
The fanatical rationality of Greek philosophy shows that they were in a state of emergency [Nietzsche]
     Full Idea: The fanaticism with which the whole of Greek thought throws itself at rationality betrays itself as a state of emergency: one was in peril, one had only one choice: either to perish or- be absurdly rational.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.10)
20. Action / B. Preliminaries of Action / 2. Willed Action / a. Will to Act
The big error is to think the will is a faculty producing effects; in fact, it is just a word [Nietzsche]
     Full Idea: At the beginning stands the great fateful error that the will is something which produces an effect - that will is a faculty.... Today we know it is merely a word.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.5)
     A reaction: This is despite Nietzsche's insistence that 'will to power' is the central fact of active existence. The misreading of Nietzsche is to think that this refers to the conscious exercising of a mental faculty.
20. Action / C. Motives for Action / 3. Acting on Reason / b. Intellectualism
The 'motive' is superficial, and may even hide the antecedents of a deed [Nietzsche]
     Full Idea: The so-called 'motive' is another error. Merely a surface phenomenon of consciousness - something alongside the deed which is more likely to cover up the antecedents of the deed than to represent them.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 6.3)
     A reaction: [Leiter gives 'VI.3', but I can't find it] As far as you can get from intellectualism about action, and is more in accord with the picture found in modern neuro-science. No one knows why they are 'interested' in something, and that's the start of it.
21. Aesthetics / A. Aesthetic Experience / 5. Natural Beauty
The beautiful never stands alone; it derives from man's pleasure in man [Nietzsche]
     Full Idea: Anyone who tried to divorce the beautiful from man's pleasure in man would at once feel the ground give way beneath him. The 'beautiful in itself' is not even a concept, merely a phrase.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.19)
     A reaction: I love the insult 'not even a concept'! It's like Pauli's 'not even wrong'!
21. Aesthetics / B. Nature of Art / 8. The Arts / a. Music
Without music life would be a mistake [Nietzsche]
     Full Idea: Without music life would be a mistake.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], Maxim 33)
     A reaction: Cf Schopenhauer in Idea 21469. If you, dear reader, don't love music, then I sincerely hope that there is something in your life which can match it.
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / a. Preconditions for ethics
Healthy morality is dominated by an instinct for life [Nietzsche]
     Full Idea: All naturalism in morality, that is all healthy morality, is dominated by an instinct for life.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 4.4)
     A reaction: Sounds right. There is no reasoning against a moral nihilist, because they seem to have no instinct in favour of life. It is the given of morality.
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / f. Ethical non-cognitivism
Philosophers hate values having an origin, and want values to be self-sufficient [Nietzsche]
     Full Idea: For philosophers, the higher must not be allowed to grow out of the lower, must not be allowed to have grown at all ...Moral: everything of the first rank must be causa sui. Origin in something else counts as an objection, as casting a doubt on value.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.4)
     A reaction: This is so deep and central that I wrote a paper on it, advocating that the theory of values should focus of value-makers.
There are no moral facts, and moralists believe in realities which do not exist [Nietzsche]
     Full Idea: An insight formulated by me: that there are no moral facts whatever. Moral judgement has this in common with religious judgement that it believes in realities which do not exist.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 6.1)
     A reaction: Not only a slogan for non-cognitivism, but also a clear statement of the error theory about morality, a century before John Mackie.
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / g. Moral responsibility
The doctrine of free will has been invented essentially in order to blame and punish people [Nietzsche]
     Full Idea: The doctrine of will has been invented essentially for the purpose of punishment, that is of finding guilty.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 5.7)
     A reaction: Michael Frede says free will was invented to feel wholly in charge of our own actions. I doubt whether punishment was the first motive. The will just gives a simple explanation of actions.
22. Metaethics / B. Value / 2. Values / c. Life
The value of life cannot be estimated [Nietzsche]
     Full Idea: The value of life cannot be estimated.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.02)
     A reaction: Military leaders apparently judge that the death of one of their own soldiers is worth between 12 and 20 enemy deaths (so history suggests). How about ransom money?
When we establish values, that is life itself establishing them, through us [Nietzsche]
     Full Idea: When we speak of values we do so under the inspiration and from the perspective of life: life itself evaluates through us when we establish values
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 4.5)
     A reaction: I love Nietzsche's ideas about the source of values, and his remarks about the value of life. Other thinkers sound so simplistic in comparison.
In every age the wisest people have judged life to be worthless [Nietzsche]
     Full Idea: In every age the wisest have passed the identical judgement on life: it is worthless.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.01)
     A reaction: I guess he was having a bad day. Since the whole universe is clearly 'worthless', this judgement must in some sense be correct. But I love my books.
A philosopher fails in wisdom if he thinks the value of life is a problem [Nietzsche]
     Full Idea: For a philosopher to see a problem in the value of life thus even constitutes an objection to him, a question-mark as to his wisdom, a piece of unwisdom.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.02)
     A reaction: I take his point to be neither that life is unquestionably valuable nor that it is valueless, but that the very question is ridiculous. If we live, we value living. Sounds right.
Value judgements about life can never be true [Nietzsche]
     Full Idea: Judgements, value judgements concerning life, for or against it, can in the last resort never be true.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 1.02)
     A reaction: I suppose this is in the same spirit as judging whether celery tastes nice. Are you for or against the Moon?
To evaluate life one must know it, but also be situated outside of it [Nietzsche]
     Full Idea: One would have to be situated outside life ....[and yet know it thoroughly] ....to be permitted to touch on the problem of the value of life at all.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 4.5)
     A reaction: Can practising artists question the value of their art? The whole point of objectivity is that we can mentally step 'outside' of something, without actually withdrawing from it.
22. Metaethics / B. Value / 2. Values / g. Love
Love is the spiritualisation of sensuality [Nietzsche]
     Full Idea: The spiritualization of sensuality is called 'love': it is a great triumph over Christianity.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 4.3)
     A reaction: I'm not quite clear what 'spiritualization' means, particularly when it comes from Nietzsche.
22. Metaethics / C. The Good / 1. Goodness / d. Good as virtue
A good human will be virtuous because they are happy [Nietzsche]
     Full Idea: A well-constituted human being, a 'happy one', must perform certain actions and shrink from other actions. In a formula: his virtue is the consequence of his happiness.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 5.2)
     A reaction: A nice reversal of basic Aristotle, though Aristotle does say that the truly virtuous person is happy in their actions. Treat unhappy people with caution!
22. Metaethics / C. The Good / 2. Happiness / c. Value of happiness
Only the English actually strive after happiness [Nietzsche]
     Full Idea: Man does not strive after happiness; only the Englishman does that.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], Maxim 12)
     A reaction: The Danes keeping being voted the happiest nation, so presumably that results from some sort of effort on their part. The easiest is happiness is to achieve security, then do nothing.
23. Ethics / A. Egoism / 1. Ethical Egoism
A wholly altruistic morality, with no egoism, is a thoroughly bad thing [Nietzsche]
     Full Idea: An 'altruistic' morality, a morality under which egoism languishes - is under all circumstances a bad sign.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.35)
23. Ethics / C. Virtue Theory / 3. Virtues / d. Courage
Military idea: what does not kill me makes me stronger [Nietzsche]
     Full Idea: From the military school of life. - What does not kill me makes me stronger.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], Maxim 08)
     A reaction: The published version! Perhaps the most famous remark in all of Nietzsche, and no one realises it is ironic! It is a sarcastic remark about the battering ram mentality of the Prussian militarist! He had served in the army.
23. Ethics / C. Virtue Theory / 3. Virtues / f. Compassion
Invalids are parasites [Nietzsche]
     Full Idea: The invalid is a parasite on society.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.36)
     A reaction: I'll skip the rest, but you get the idea. The point (with which I sympathise) is that life is primarily about what healthy people do. Something has gone wrong if all we do is worry about the sick and the suffering.
24. Political Theory / D. Ideologies / 5. Democracy / f. Against democracy
Democracy is organisational power in decline [Nietzsche]
     Full Idea: Democracy has always been the declining form of the power to organise.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.39)
     A reaction: Even when Nietzsche is wrong (and who knows, here?) he always challenges you to think!
24. Political Theory / D. Ideologies / 6. Liberalism / g. Liberalism critique
The creation of institutions needs a determination which is necessarily anti-liberal [Nietzsche]
     Full Idea: For institutions to exist there must exist the kind of will, instinct, imperative which is anti-liberal to the point of malice: the will to tradition, to authority, to centuries-long responsibility, to solidarity between succeeding generations.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.39)
     A reaction: This sounds like a lovely challenge to Popper, who seems to have been a liberal who pinned his faith on institutions.
25. Social Practice / D. Justice / 1. Basis of justice
True justice is equality for equals and inequality for unequals [Nietzsche]
     Full Idea: 'Equality for equals, inequality for unequals' - that would be the true voice of justice.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.48)
25. Social Practice / E. Policies / 1. War / a. Just wars
To renounce war is to renounce the grand life [Nietzsche]
     Full Idea: One has renounced grand life when one renounces war.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 4.3)
     A reaction: Nietzsche was a medical orderly in the 1870 Franco-Prussian war, so he had seen it at first hand. I think the machine gun and the heavy bomber would have changed his attitude to warfare. He sounds a bit silly now. Nostalgia for the Iliad.
25. Social Practice / E. Policies / 5. Education / c. Teaching
There is a need for educators who are themselves educated [Nietzsche]
     Full Idea: There is a need for educators who are themselves educated.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 7.5)
25. Social Practice / F. Life Issues / 4. Suicide
Sometimes it is an error to have been born - but we can rectify it [Nietzsche]
     Full Idea: We have no power to prevent ourselves being born: but we can rectify this error - for sometimes it is an error.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.36)
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / c. Purpose denied
'Purpose' is just a human fiction [Nietzsche]
     Full Idea: We invented the concept 'purpose': in reality purpose is lacking.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 5.8)
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
The supreme general but empty concepts must be compatible, and hence we get 'God' [Nietzsche]
     Full Idea: The supreme concepts of philosophers cannot be incommensurate with one another, be incompatible with one another... Thus they acquired their stupendous concept 'God'.... The last, thinnest, emptiest is placed as the first, as cause in itself.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.4)
28. God / C. Attitudes to God / 5. Atheism
By denying God we deny human accountability, and thus we redeem the world [Nietzsche]
     Full Idea: We deny God; in denying God we deny accountability; only by doing that do we redeem the world.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 5.8)
29. Religion / B. Monotheistic Religion / 4. Christianity / a. Christianity
How could the Church intelligently fight against passion if it preferred poorness of spirit to intelligence? [Nietzsche]
     Full Idea: The primitive church fought against the 'intelligent' in favour of the 'poor in spirit': how could one expect from it an intelligent war against passion?
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 4.1)
Christians believe that only God can know what is good for man [Nietzsche]
     Full Idea: Christianity presupposes that man does not know, cannot know what is good for him and what evil: he believes in God, who alone knows.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 8.05)
29. Religion / D. Religious Issues / 2. Immortality / d. Heaven
People who disparage actual life avenge themselves by imagining a better one [Nietzsche]
     Full Idea: If there is a strong instinct for slandering, disparaging and accusing life within us, then we revenge ourselves on life by means of the phantasmagoria of 'another', a 'better' life.
     From: Friedrich Nietzsche (Twilight of the Idols [1889], 2.6)