Combining Texts

All the ideas for 'Conditionals', 'Dialogue on human freedom and origin of evil' and 'Letter to Weber'

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9 ideas

6. Mathematics / A. Nature of Mathematics / 2. Geometry

13163	Circles must be bounded, so cannot be infinite [Leibniz]
	Full Idea: An infinite circle is impossible, since any circle is bounded by its circumference.
	From: Gottfried Leibniz (Dialogue on human freedom and origin of evil [1695], p.114)
	A reaction: This is interesting if one is asking what the essence of a circle must be. If is tempting to say merely that the radii must be equal, but can they have the length of some vast transfinite number? The circumference must be 2π bigger.

6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts

18244	I say the irrational is not the cut itself, but a new creation which corresponds to the cut [Dedekind]
	Full Idea: Of my theory of irrationals you say that the irrational number is nothing else than the cut itself, whereas I prefer to create something new (different from the cut), which corresponds to the cut. We have the right to claim such a creative power.
	From: Richard Dedekind (Letter to Weber [1888], 1888 Jan), quoted by Stewart Shapiro - Philosophy of Mathematics 5.4
	A reaction: Clearly a cut will not locate a unique irrational number, so something more needs to be done. Shapiro remarks here that for Dedekind numbers are objects.

10. Modality / B. Possibility / 8. Conditionals / a. Conditionals

13768	Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
	Full Idea: If your interest in logic is confined to applications to mathematics or other a priori matters, it is fine for validity to preserve certainty, ..but if you use conditionals when arguing about contingent matters, then great caution will be required.
	From: Dorothy Edgington (Conditionals [2001], 17.2.1)

10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional

13770	There are many different conditional mental states, and different conditional speech acts [Edgington]
	Full Idea: As well as conditional beliefs, there are conditional desires, hopes, fears etc. As well as conditional statements, there are conditional commands, questions, offers, promises, bets etc.
	From: Dorothy Edgington (Conditionals [2001], 17.3.4)

10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals

13764	Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
	Full Idea: Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? Are they non-truth-functional, like 'because' or 'before'? Do the values of A and B, in some cases, leave open the value of 'If A,B'?
	From: Dorothy Edgington (Conditionals [2001], 17.1)
	A reaction: I would say they are not truth-functional, because the 'if' asserts some further dependency relation that goes beyond the truth or falsity of A and B. Logical ifs, causal ifs, psychological ifs... The material conditional ⊃ is truth-functional.

13765	'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]
	Full Idea: If it were possible to have A true, B false, and If A,B true, it would be unsafe to infer B from A and If A,B: modus ponens would thus be invalid. Hence 'If A,B' must entail ¬(A & ¬B).
	From: Dorothy Edgington (Conditionals [2001], 17.1)
	A reaction: This is a firm defence of part of the truth-functional view of conditionals, and seems unassailable. The other parts of the truth table are open to question, though, if A is false, or they are both true.

16. Persons / F. Free Will / 6. Determinism / b. Fate

13162	Sloth's Syllogism: either it can't happen, or it is inevitable without my effort [Leibniz]
	Full Idea: The ancient Sloth's Syllogism says that if something is foreseen and infallible, it will happen without my effort, and if it is not foreseen, it will not happen, even though I am able to do it.
	From: Gottfried Leibniz (Dialogue on human freedom and origin of evil [1695], p.113)
	A reaction: Presumable the foreseeing is to be done by the oracle, and not by the slothful person.

29. Religion / D. Religious Issues / 3. Problem of Evil / a. Problem of Evil

19339	Evil is a negation of good, which arises from non-being [Leibniz]
	Full Idea: The cause of good is positive, but evil is a defect, that is, a privation or negation, and consequently, it arises from nothingness or nonbeing.
	From: Gottfried Leibniz (Dialogue on human freedom and origin of evil [1695], p.114)
	A reaction: He goes on to illustrate his idea from mathematics. He is modifying Augustine's view that evil is an absence of good, by adding nonbeing as the driving force behind it. Doesn't sound very persuasive to me.

13164	God only made sin possible because a much greater good can be derived from it [Leibniz]
	Full Idea: We must believe that God would not have allowed sin nor would he have created things he knows will sin, if he could not derive from them a good incomparably greater than the resulting evil.
	From: Gottfried Leibniz (Dialogue on human freedom and origin of evil [1695], p.115)
	A reaction: Why 'must' we believe this? Do we have to imagine all the genocides shrinking to insignificance once we grasp the wonderful goods that can be derived from them? The end justifies the means. Genocide is actually a good thing. Hm.