12 ideas
1564 | True and false statements can use exactly the same words [Anon (Diss)] |
Full Idea: There is no difference between a true statement and a false statement, because they can use exactly the same words. | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §4) |
17744 | De Morgan started the study of relations and their properties [De Morgan, by Walicki] |
Full Idea: De Morgan started the sustained interest in the study of relations and their properties. | |
From: report of Augustus De Morgan (On the Syllogism IV [1859]) by Michal Walicki - Introduction to Mathematical Logic History D.1.1 |
13501 | De Morgan found inferences involving relations, which eluded Aristotle's syllogistic [De Morgan, by Hart,WD] |
Full Idea: There was a prejudice against relations (in favour of properties) but De Morgan and others that impeccable inferences turn on relations and elude Aristotle's syllogistic. Thus: All horses are animals. Hence, all heads of horses are heads of animals. | |
From: report of Augustus De Morgan (On the Syllogism IV [1859]) by William D. Hart - The Evolution of Logic 4 | |
A reaction: This is actually an early example of modern analytic philosophy in action. You start with the inferences, and then work back to the ontology and the definition of concepts. But in pinning down such concepts, do we miss their full meaning? |
14283 | A conditional probability does not measure the probability of the truth of any proposition [Lewis, by Edgington] |
Full Idea: Lewis was first to prove this remarkable result: there is no proposition A*B such that, in all probability distributions, p(A*B) = pA(B) [second A a subscript]. A conditional probability does not measure the probability of the truth of any proposition. | |
From: report of David Lewis (Probabilities of Conditionals [1976]) by Dorothy Edgington - Conditionals (Stanf) 3.1 | |
A reaction: The equation says the probability of the combination of A and B is not always the same as the probability of B given A. Bennett refers to this as 'The Equation' in the theory of conditionals. Edgington says a conditional is a supposition and a judgement. |
1561 | Anything can be acceptable in some circumstances and unacceptable in others [Anon (Diss)] |
Full Idea: Anything can be acceptable under the right circumstances, and unacceptable under the wrong circumstances. | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §2) |
1560 | Lydians prostitute their daughters to raise a dowery, but no Greek would marry such a girl [Anon (Diss)] |
Full Idea: The Lydians find it acceptable for their daughters to work as prostitutes to raise money for getting married, but no one in Greece would be prepared to marry such a girl. | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §2) |
1559 | Thracians think tattooing adds to a girl's beauty, but elsewhere it is a punishment [Anon (Diss)] |
Full Idea: Thracians think that tattooing enhances a girl's beauty, whereas for everyone else tattooing is a punishment for a crime. | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §2) |
1567 | How could someone who knows everything fail to act correctly? [Anon (Diss)] |
Full Idea: If someone knows the nature of everything, how could he fail to be able also to act correctly in every case? | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §8) |
1563 | Every apparent crime can be right in certain circumstances [Anon (Diss), by PG] |
Full Idea: It can be right, in certain circumstances, to steal, to break a solemn promise, to rob temples, and even (as Orestes did) to murder one's nearest and dearest. | |
From: report of Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §3) by PG - Db (ideas) | |
A reaction: Not sure about the last one! I suppose you can justify any hideousness if the fate of the universe depends on it. It must be better to die than the perform certain extreme deeds. |
1562 | It is right to lie to someone, to get them to take medicine they are reluctant to take [Anon (Diss)] |
Full Idea: It is right to lie to your parents, in order to get them to take a good medicine they are reluctant to take. | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §3) | |
A reaction: I dread to think what the medicines were which convinced the writer of this. A rule such as this strikes me as dangerous. Justifiable in extreme cases. House on fire etc. |
1566 | The first priority in elections is to vote for people who support democracy [Anon (Diss)] |
Full Idea: A lottery is not democratic, because every state contains people who are not democratic, and if the lottery chooses them they will destroy the democracy. People should elect those who are observed to favour democracy. | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §7) |
1565 | We learn language, and we don't know who teaches us it [Anon (Diss)] |
Full Idea: We learn language, and we don't know who teaches us it. | |
From: Anon (Diss) (Dissoi Logoi - on Double Arguments [c.401 BCE], §6) |