Combining Texts

All the ideas for 'Prologue to Ordinatio', 'Equality' and 'An Introduction to Modal Logic'

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14 ideas

4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell]
     Full Idea: A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0.
     From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1)
     A reaction: In the interpreted version of the logic, 1 and 0 would become T (true) and F (false). The procedure seems to be called nowadays a 'valuation'.
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell]
     Full Idea: The Law of Transposition says that (P→Q) → (¬Q→¬P).
     From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1)
     A reaction: That is, if the consequent (Q) of a conditional is false, then the antecedent (P) must have been false.
4. Formal Logic / B. Propositional Logic PL / 4. Soundness of PL
The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell]
     Full Idea: An axiomatic system is most naturally consistent iff no thesis is the negation of another thesis. It can be shown that every axiom is valid, that the transformation rules are validity-preserving, and if a wff α is valid, then ¬α is not valid.
     From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1)
     A reaction: [The labels 'soundness' and 'consistency' seem interchangeable here, with the former nowadays preferred]
5. Theory of Logic / K. Features of Logics / 4. Completeness
A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell]
     Full Idea: To say that an axiom system is 'weakly complete' is to say that every valid wff of the system is derivable as a thesis. ..The system is 'strongly complete' if it cannot have any more theses than it has without falling into inconsistency.
     From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1)
     A reaction: [They go on to say that Propositional Logic is strongly complete, but Modal Logic is not]
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
Our intellect only assents to what we believe to be true [William of Ockham]
     Full Idea: Our intellect does not assent to anything unless we believe it to be true.
     From: William of Ockham (Prologue to Ordinatio [1320], Q 1 N sqq)
     A reaction: This strikes me as being a much more accurate and commonsense view of belief than that of Hume, who simply views it phenomenologically. ...But then the remark appears to be circular. Belief requires a belief that it is true. Hm.
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
Abstractive cognition knows universals abstracted from many singulars [William of Ockham]
     Full Idea: Abstractive cognition (in one sense) relates to something abstracted from many singulars; and in this sense abstractive cognition is nothing else but cognition of a universal which can be abstracted from many things.
     From: William of Ockham (Prologue to Ordinatio [1320], Q 1 N sqq)
     A reaction: This strikes me as being correct common sense, even though it has become deeply unfashionable since Frege. We may not be able to see quite how the mind manages to see universals in a bunch of objects, but there is no better story.
23. Ethics / D. Deontological Ethics / 3. Universalisability
The general form of moral reasoning is putting yourself in other people's shoes [Nagel]
     Full Idea: I believe the general form of moral reasoning is to put yourself in other people's shoes.
     From: Thomas Nagel (Equality [1977], §9)
24. Political Theory / A. Basis of a State / 4. Original Position / c. Difference principle
An egalitarian system must give priority to those with the worst prospects in life [Nagel]
     Full Idea: What makes a system egalitarian is the priority it gives to the claims of those whose overall life prospects put them at the bottom.
     From: Thomas Nagel (Equality [1977], §6)
25. Social Practice / B. Equalities / 1. Grounds of equality
Equality was once opposed to aristocracy, but now it opposes public utility and individual rights [Nagel]
     Full Idea: Egalitarianism was once opposed to aristocratic values, but now it is opposed by adherents of two non-aristocratic values: utility (increase benefit, even if unequally) and individual rights (which redistribution violates).
     From: Thomas Nagel (Equality [1977], §2)
The ideal of acceptability to each individual underlies the appeal to equality [Nagel]
     Full Idea: The ideal of acceptability to each individual underlies the appeal to equality.
     From: Thomas Nagel (Equality [1977], §8)
In judging disputes, should we use one standard, or those of each individual? [Nagel]
     Full Idea: In assessing equality of claims, it must be decided whether to use a single, objective standard, or whether interests should be ranked by the person's own estimation. Also should they balance momentary or long-term needs?
     From: Thomas Nagel (Equality [1977], §6)
25. Social Practice / B. Equalities / 2. Political equality
Equality can either be defended as good for society, or as good for individual rights [Nagel]
     Full Idea: The communitarian defence of equality says it is good for society as a whole, whereas the individualistic defence defends equality as a correct distributive principle.
     From: Thomas Nagel (Equality [1977], §2)
Equality nowadays is seen as political, social, legal and economic [Nagel]
     Full Idea: Contemporary political debate recognises four types of equality: political, social, legal and economic.
     From: Thomas Nagel (Equality [1977], §1)
     A reaction: Meaning equality of 1) power and influence, 2) status and respect, 3) rights and justice, 4) wealth.
25. Social Practice / C. Rights / 1. Basis of Rights
A morality of rights is very minimal, leaving a lot of human life without restrictions or duties [Nagel]
     Full Idea: The morality of rights tends to be a limited, even minimal, morality. It leaves a great deal of human life ungoverned by moral restrictions or requirements.
     From: Thomas Nagel (Equality [1977], §5)