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All the ideas for 'On the Question of Absolute Undecidability', 'Reflections on Knowledge, Truth and Ideas' and 'On the Law of War and Peace'

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19 ideas

2. Reason / D. Definition / 1. Definitions
'Nominal' definitions just list distinguishing characteristics [Leibniz]
     Full Idea: A 'nominal' definition is nothing more than an enumeration of the sufficient distinguishing characteristics.
     From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.284)
     A reaction: Not wholly clear. Are these actual distinguishing characteristics, or potential ones? Could DNA be part of a human's nominal definition (for an unidentified corpse, perhaps).
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner]
     Full Idea: There are many coherent stopping points in the hierarchy of increasingly strong mathematical systems, starting with strict finitism, and moving up through predicativism to the higher reaches of set theory.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], Intro)
'Reflection principles' say the whole truth about sets can't be captured [Koellner]
     Full Idea: Roughly speaking, 'reflection principles' assert that anything true in V [the set hierarchy] falls short of characterising V in that it is true within some earlier level.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 2.1)
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
We have no argument to show a statement is absolutely undecidable [Koellner]
     Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
There are at least eleven types of large cardinal, of increasing logical strength [Koellner]
     Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable).
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
     A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner]
     Full Idea: To the extent that we are justified in accepting Peano Arithmetic we are justified in accepting its consistency, and so we know how to expand the axiom system so as to overcome the limitation [of Gödel's Second Theorem].
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.1)
     A reaction: Each expansion brings a limitation, but then you can expand again.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Arithmetical undecidability is always settled at the next stage up [Koellner]
     Full Idea: The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
11. Knowledge Aims / A. Knowledge / 1. Knowledge
Knowledge needs clarity, distinctness, and adequacy, and it should be intuitive [Leibniz]
     Full Idea: Knowledge is either obscure or clear; clear ideas are either indistinct or distinct; distinct ideas are either adequate or inadequate, symbolic or intuitive; perfect knowledge is that which is both adequate and intuitive.
     From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.283)
     A reaction: This is Leibniz's expansion of Descartes's idea that knowledge rests on 'clear and distinct conceptions'. The ultimate target seems to be close to an Aristotelian 'real definition', which is comprehensive and precise. Does 'intuitive' mean coherent?
18. Thought / C. Content / 2. Ideas
True ideas represent what is possible; false ideas represent contradictions [Leibniz]
     Full Idea: An idea is true if what it represents is possible; false if the representation contains a contradiction.
     From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.287)
     A reaction: Odd in the analytic tradition to talk of a single idea or concept (rather than a proposition or utterance) as being 'true'. But there is clearly a notion of valid or legitimate or useful concepts here. Hilbert said true just meant non-contradictory.
20. Action / C. Motives for Action / 5. Action Dilemmas / c. Omissions
Nations are not obliged to help one-another, but are obliged not to harm one another [Grotius, by Tuck]
     Full Idea: Grotius explored the implications of the idea that nation-states were under no obligation to help one another, but they were obliged not to harm each other.
     From: report of Hugo Grotius (On the Law of War and Peace [1625]) by Richard Tuck - Hobbes Ch.1
     A reaction: This is quite a striking disanalogy between accepted personal morality and political morality. There are signs in recent years of some recognition that other nations should not just sit and watch suffering.
24. Political Theory / A. Basis of a State / 3. Natural Values / c. Natural rights
Everyone has a right of self-preservation, and harming others is usually unjustifiable [Grotius, by Tuck]
     Full Idea: Grotius said that all men would agree that everyone has a fundamental right to preserve themselves, and that wanton or unnecessary injury to another person is unjustifiable.
     From: report of Hugo Grotius (On the Law of War and Peace [1625]) by Richard Tuck - Hobbes Ch.1
     A reaction: Who cares if it is 'justifiable'? Do I have to 'justify' killing a mosquito if it lands on my arm? Grotius is taking a step beyond saying that people should defend themselves, to say that they have a 'right' to - the only truly basic right.
24. Political Theory / D. Ideologies / 5. Democracy / a. Nature of democracy
Democracy needs respect for individuality, but the 'community of friends' implies strict equality [Grotius]
     Full Idea: There is no democracy without respect for irreducible singularity, but there is no democracy with the 'community of friends' without the calculation of majorities, without identifiable representable subjects, all equal.
     From: Hugo Grotius (On the Law of War and Peace [1625]), quoted by Simon Glendinning - Derrida: A Very Short Introduction 7
     A reaction: [source not given] Derrida calls this conflict 'tragic'. The obvious reply is that equality is not an absolute. We can be equal in voting rights while being unequal in height or musical talent.
25. Social Practice / A. Freedoms / 7. Freedom to leave
A person is free to renounce their state, as long as it is not a moment of crisis [Grotius, by Rousseau]
     Full Idea: Grotius thinks that each person can renounce his state and leave the country. (n15: provided it is not to evade one's duty the moment the homeland needs us; this would be criminal and punishable; it would not be withdrawal, but desertion)
     From: report of Hugo Grotius (On the Law of War and Peace [1625]) by Jean-Jacques Rousseau - The Social Contract (tr Cress) III.18
     A reaction: The obvious example is Britons going to America in 1939, or (more controversially) conscripts going to Canada to avoid fighting in Vietnam. I'm unclear whether the idea in the note is that of Grotius or of Rousseau). Is tax exile OK, then?
25. Social Practice / D. Justice / 2. The Law / c. Natural law
Grotius and Pufendorf based natural law on real (rather than idealised) humanity [Grotius, by Ford,JD]
     Full Idea: Grotius and Pufendorf transformed the natural law tradition by starting from identifiable traits of human nature rather than ideas about what human beings ought to be.
     From: report of Hugo Grotius (On the Law of War and Peace [1625]) by J.D. Ford - Pufendorf, Samuel p.863
A natural right of self-preservation is balanced by a natural law to avoid unnecessary harm [Grotius, by Tuck]
     Full Idea: For Grotius, there was a fundamental 'natural right' of self-preservation upon which all known moralities and codes of social behaviour must have been constructed, but it is balanced by a fundament duty or 'natural law' to abstain from harming others.
     From: report of Hugo Grotius (On the Law of War and Peace [1625]) by Richard Tuck - Hobbes Ch.2
     A reaction: This theory has the virtue of economy, but I don't see how you can clearly justify those particular natural rights and laws, without allowing others to creep in, such as a right to a decent share of food, or a law requiring some fairness.
25. Social Practice / D. Justice / 2. The Law / d. Legal positivism
Grotius ignored elaborate natural law theories, preferring a basic right of self-preservation [Grotius, by Tuck]
     Full Idea: Grotius said there was a minimum core of morality (based on self-preservation), and disregarded the elaborate accounts of principles of natural law which Aristotelians had always sought to develop.
     From: report of Hugo Grotius (On the Law of War and Peace [1625]) by Richard Tuck - Hobbes Ch.1
     A reaction: Aquinas would be the key Aristotelian here. I tend towards the Aristotelian view. If you go for the minimal view, it is not clear why there is a 'right' to self-preservation, rather than a mere desire for it.
25. Social Practice / E. Policies / 1. War / b. Justice in war
It is permissible in a just cause to capture a place in neutral territory [Grotius]
     Full Idea: It is permissible for one who is waging a just war to take possession of a place situated in a country free from hostilities.
     From: Hugo Grotius (On the Law of War and Peace [1625], II.ii.x), quoted by Michael Walzer - Just and Unjust Wars 15 n
     A reaction: This rejects Combatant Equality, allowing the just to do what is morally forbidden to the unjust.
26. Natural Theory / C. Causation / 2. Types of cause
In the schools the Four Causes are just lumped together in a very obscure way [Leibniz]
     Full Idea: In the schools the four causes are lumped together as material, formal, efficient, and final causes, but they have no clear definitions, and I would call such a judgment 'obscure'.
     From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.283)
     A reaction: He picks this to illustrate what he means by 'obscure', so he must feel strongly about it. Elsewhere Leibniz embraces efficient and final causes, but says little of the other two. This immediately become clearer as the Four Modes of Explanation.
28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
Moral principles have some validity without a God commanding obedience [Grotius, by Mautner]
     Full Idea: In the Prolegomena to his work there is a famous statement that moral principles laid down in the work would have some degree of validity even if there was no God commanding obedience.
     From: report of Hugo Grotius (On the Law of War and Peace [1625]) by Thomas Mautner - Penguin Dictionary of Philosophy p.229
     A reaction: I am not clear why Grotius felt obliged to qualify his claim with the phrase 'some degree'. I don't see how God's command can affect the 'validity' of morality, or how there can be a middle ground between dependence on and independence of God.