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All the ideas for 'On the Philosophy of Logic', 'Fragments' and 'What is Philosophy?'

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25 ideas

1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Philosophy is in a perpetual state of digression [Deleuze/Guattari]
     Full Idea: Philosophy can be seen as being in a perpetual state of digression.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1)
     A reaction: Anyone who has ever tried to teach philosophy will vouch for this. Philosophy is the 'Arabian Nights', conjuring up wonderful stories, to avoid having to face something nasty. Philosophy is perpetual postponement of problems.
1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
Philosophy is a concept-creating discipline [Deleuze/Guattari]
     Full Idea: Philosophy is the discipline that involves creating concepts.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], Intro)
     A reaction: One might very reasonably reply that Geography is a discipline which creates concepts. However, this emphasis is an interesting corrective to the school of analysis, which appears confined to existing, and even 'folk', concepts.
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
Philosophy aims at what is interesting, remarkable or important - not at knowledge or truth [Deleuze/Guattari]
     Full Idea: Philosophy does not consist in knowing, and is not inspired by truth. Rather, it is categories like Interesting, Remarkable, or Important that determine success or failure.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.3)
     A reaction: Speak for yourself. I wonder what the criteria are for 'Interesting' or 'Important'. They can't seriously count 'remarkable' as a criterion of philosophical success, can they? There can be remarkable stupidity.
1. Philosophy / H. Continental Philosophy / 1. Continental Philosophy
The plague of philosophy is those who criticise without creating, and defend dead concepts [Deleuze/Guattari]
     Full Idea: Those who criticise without creating, those who are content to defend the vanished concept without being able to give it the forces it needs to return to life, are the plague of philosophy.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1)
     A reaction: This seems to be the continental view of analytical philosophy, that it is pathetically conservative. I would offer MacIntyre as a response, who gives a beautiful analysis of why the super-modern view is dead. The French are hopelessly romantic.
1. Philosophy / H. Continental Philosophy / 2. Phenomenology
Phenomenology needs art as logic needs science [Deleuze/Guattari]
     Full Idea: Phenomenology needs art as logic needs science.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 2.6)
     A reaction: I would have thought that it was science that needs logic. Art is more elitist than science, and less universal. I presume artists and phenomenologists share a target of deconstructing lived human experience.
2. Reason / A. Nature of Reason / 1. On Reason
We reach 'reflective equilibrium' when intuitions and theory completely align [Fisher]
     Full Idea: A state of 'reflective equilibrium' is when our theory and our intuitions become completely aligned
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.IV)
     A reaction: [Rawls made this concept famous] This is a helpful concept in trying to spell out the ideal which is the dream of believers in 'pure reason' - that there is a goal in which everything comes right. The problem is when people have different intuitions!
2. Reason / C. Styles of Reason / 3. Eristic
'Eris' is the divinity of conflict, the opposite of Philia, the god of friendship [Deleuze/Guattari]
     Full Idea: 'Eris' is the Greek divinity of discord, conflict, and strife, the complementary opposite of Philia, the divinity of union and friendship.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.2 n)
     A reaction: Are these actual gods? This interestingly implies that the wonders of dialectic and Socrates' elenchus are simply aspects of friendship, which was elevated by Epicurus to the highest good. The Greeks just wanted wonderful friends and fine speeches.
4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
Three-valued logic says excluded middle and non-contradition are not tautologies [Fisher]
     Full Idea: In three-valued logic (L3), neither the law of excluded middle (p or not-p), nor the law of non-contradiction (not(p and not-p)) will be tautologies. If p has the value 'indeterminate' then so will not-p.
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.I)
     A reaction: I quite accept that the world is full of indeterminate propositions, and that excluded middle and non-contradiction can sometimes be uncertain, but I am reluctant to accept that what is being offered here should be called 'logic'.
4. Formal Logic / E. Nonclassical Logics / 4. Fuzzy Logic
Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher]
     Full Idea: In fuzzy logic objects have properties to a greater or lesser degree, and truth values are given as fractions or decimals, ranging from 0 to 1. Not-p is defined as 1-p, and other formula are defined in terms of maxima and minima for sets.
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II)
     A reaction: The question seems to be whether this is actually logic, or a recasting of probability theory. Susan Haack attacks it. If logic is the study of how truth is preserved as we move between propositions, then 0 and 1 need a special status.
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Logic has an infantile idea of philosophy [Deleuze/Guattari]
     Full Idea: Logic has an infantile idea of philosophy.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1)
     A reaction: This offers some explanation of why Anglo-American philosophers are steeped in logic, and the continentals just ignore it. I have some sympathy with the French view. Logic seems to study language with all the interesting part drained off.
Logic hates philosophy, and wishes to supplant it [Deleuze/Guattari]
     Full Idea: A real hatred inspires logic's rivalry with, or its will to supplant, philosophy.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 2.6)
     A reaction: A delightful corrective to the neurotic inferiority that most English-speaking philosophers feel about their failure to master logic. What was Aristotle playing at when he invented logic? Philosophical talent is utterly different from a talent for logic.
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher]
     Full Idea: For simplicity, we can say that 'classical logic' amounts to the truth of four sentences: 1) either p or not-p; 2) it is not the case that both p and not-p; 3) from p and not-p, infer q; 4) from p or q and not-p, infer q.
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.I)
     A reaction: [She says there are many ways of specifying classical logic] Intuition suggests that 2 and 4 are rather hard to dispute, while 1 is ignoring some grey areas, and 3 is totally ridiculous. There is, of course, plenty of support for 3!
5. Theory of Logic / C. Ontology of Logic / 2. Platonism in Logic
Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher]
     Full Idea: Even if one is inclined to be a realist about everything, it is hard to see why our logic should be the determiner. Logic is supposed to formalize how we ought to reason, but whether or not we should be realists is a matter of philosophy, not logic.
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 09.I)
     A reaction: Nice to hear a logician saying this. I do not see why talk in terms of an object is a commitment to its existence. We can discuss the philosopher's stone, or Arthur's sword, or the Loch Ness monster, or gravitinos, with degrees of commitment.
7. Existence / D. Theories of Reality / 10. Vagueness / g. Degrees of vagueness
We could make our intuitions about heaps precise with a million-valued logic [Fisher]
     Full Idea: We could construct a 1,000,000-valued logic that would allow our intuitions concerning a heap to vary exactly with the amount of sand in the heap.
     From: Jennifer Fisher (On the Philosophy of Logic [2008])
     A reaction: Presumably only an infinite number of grains of sand would then produce a true heap, and even one grain would count as a bit of a heap, which must both be wrong, so I can't see this helping much.
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
Vagueness can involve components (like baldness), or not (like boredom) [Fisher]
     Full Idea: Vague terms come in at least two different kinds: those whose constituent parts come in discrete packets (bald, rich, red) and those that don't (beauty, boredom, niceness).
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II)
     A reaction: The first group seem to be features of the external world, and the second all occur in the mind. Baldness may be vague, but presumably hairs are (on the whole) not. Nature doesn't care whether someone is actually 'bald' or not.
10. Modality / B. Possibility / 1. Possibility
We can't explain 'possibility' in terms of 'possible' worlds [Fisher]
     Full Idea: Explaining 'it is possible that p' by saying p is true in at least one possible world doesn't get me very far. If I don't understand what possibility is, then appealing to possible worlds is not going to do me much good.
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 06.III)
     A reaction: This seems so blatant that I assume friends of possible worlds will have addressed the problem. Note that you will also need to understand 'possible' to define necessity as 'true in all possible worlds'. Necessarily-p is not-possibly-not-p.
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
If all truths are implied by a falsehood, then not-p might imply both q and not-q [Fisher]
     Full Idea: If all truths are implied by a falsehood, then 'if there are no trees in the park then there is no shade' and 'if there are no trees in the park there is plenty of shade' both come out as true. Intuitively, though, the second one is false.
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.I)
     A reaction: The rule that a falsehood implies all truths must be the weakest idea in classical logic, if it actually implies a contradiction. This means we must take an interest in relevance logics.
10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
In relevance logic, conditionals help information to flow from antecedent to consequent [Fisher]
     Full Idea: A good account of relevance logic suggests that a conditional will be true when the flow of information is such that a conditional is the device that helps information to flow from the antecedent to the consequent.
     From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.III)
     A reaction: Hm. 'If you are going out, you'll need an umbrella'. This passes on information about 'out', but also brings in new information. 'If you are going out, I'm leaving you'. What flows is an interpretation of the antecedent. Tricky.
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
We cannot judge the Cogito. Must we begin? Must we start from certainty? Can 'I' relate to thought? [Deleuze/Guattari]
     Full Idea: There is no point in wondering whether Descartes' Cogito is right or wrong. Is it necessary "to begin", and, if so, is it necessary to start from the point of view of a subjective certainty? Can thought be the verb of an I? There is no direct answer.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1)
     A reaction: A nice first sentence for a work of philosophy would be "It is necessary to begin". Is the Cogito the only idea that is beyond judgement? I fear a slippery slope here, which would paralyse all of our judgements - and would therefore be ridiculous.
14. Science / B. Scientific Theories / 4. Paradigm
Concepts are superior because they make us more aware, and change our thinking [Deleuze/Guattari]
     Full Idea: If one concept is 'better' than an earlier one, it is because it makes us aware of new variations and unknown resonances, it carries out unforeseen cuttings-out, it brings forth an Event that surveys (survole) us.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1)
     A reaction: I don't get much of that, but it is certainly in tune with the Kuhn/Feyerabend idea that what science can generate is fresh visions, rather than precisely expanded truths. Personally I consider it dangerous nonsense, but I thought I ought to pass it on.
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / a. Other minds
Other people completely revise our perceptions, because they are possible worlds [Deleuze/Guattari]
     Full Idea: The concept of the Other Person as expression of a possible world in a perceptual field leads us to consider the components of this field in a new way.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1)
     A reaction: I like the idea that other people are possible worlds. You can give reductionist accounts of the human animal till the cows come home, but when one walk into your visual field, the mind takes off. See Crusoe and Friday.
18. Thought / C. Content / 6. Broad Content
Phenomenology says thought is part of the world [Deleuze/Guattari]
     Full Idea: According to phenomenology, thought depends on man's relations with the world - with which the brain is necessarily in agreement because it is drawn from these relations.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], Conclusion)
     A reaction: The development of externalist views of mind, arising from the Twin Earth idea, seems to provide a link to continental philosophy, where similar ideas are found in Husserl, Sartre and Merleau-Ponty. So study science, psychology, or sociology?
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
The logical attitude tries to turn concepts into functions, when they are really forms or forces [Deleuze/Guattari]
     Full Idea: Logic is reductionist not accidentally, but essentially and necessarily: following the route marked out by Frege and Russell, it wants to turn the concept into a function (...when actually a concept is a form, or a force).
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 2.6)
     A reaction: [Last part on p.144] I'm not sure that I understand 'form or force', but the idea that concepts are mere functions is like describing something as 'transport', without saying whether it is bus/bike/train.. Is a concept a vision, or a tool?
25. Social Practice / E. Policies / 5. Education / d. Study of history
Dividing history books into separate chapters is disastrous [Weil]
     Full Idea: The division of history textbooks into chapters will cost us many disastrous mistakes.
     From: Simone Weil (Fragments [1936], p.131)
     A reaction: Nice observation. The point is that we fail to grasp what really happened if we draw sharp lines across history.
28. God / C. Attitudes to God / 5. Atheism
Atheism is the philosopher's serenity, and philosophy's achievement [Deleuze/Guattari]
     Full Idea: It is amazing that so many philosophers take the death of God as tragic. Atheism is not a drama, but the philosopher's serenity and philosophy's achievement.
     From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.4)
     A reaction: It seems to me that it is the late nineteenth and early twentieth century that feels the death of God as a tragedy. Modern Anglo-American philosophers are mostly pretty serene on the subject, unless, like Dennett, they go on the offensive.