13 ideas
| 10882 | Predicative definitions only refer to entities outside the defined collection [Horsten] |
| Full Idea: Definitions are called 'predicative', and are considered sound, if they only refer to entities which exist independently from the defined collection. | |
| From: Leon Horsten (Philosophy of Mathematics [2007], §2.4) |
| 10884 | A theory is 'categorical' if it has just one model up to isomorphism [Horsten] |
| Full Idea: If a theory has, up to isomorphism, exactly one model, then it is said to be 'categorical'. | |
| From: Leon Horsten (Philosophy of Mathematics [2007], §5.2) |
| 14775 | Numbers are just names devised for counting [Peirce] |
| Full Idea: Numbers are merely a system of names devised by men for the purpose of counting. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], II) | |
| A reaction: This seems a perfectly plausible view prior to the advent of Cantor, set theory and modern mathematical logic. I suppose the modern reply to this is that Peirce may be right about origin, but that men thereby stumbled on an Aladdin's Cave of riches. |
| 10885 | Computer proofs don't provide explanations [Horsten] |
| Full Idea: Mathematicians are uncomfortable with computerised proofs because a 'good' proof should do more than convince us that a certain statement is true. It should also explain why the statement in question holds. | |
| From: Leon Horsten (Philosophy of Mathematics [2007], §5.3) |
| 10881 | The concept of 'ordinal number' is set-theoretic, not arithmetical [Horsten] |
| Full Idea: The notion of an ordinal number is a set-theoretic, and hence non-arithmetical, concept. | |
| From: Leon Horsten (Philosophy of Mathematics [2007], §2.3) |
| 14776 | That two two-eyed people must have four eyes is a statement about numbers, not a fact [Peirce] |
| Full Idea: To say that 'if' there are two persons and each person has two eyes there 'will be' four eyes is not a statement of fact, but a statement about the system of numbers which is our own creation. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], II) | |
| A reaction: One eye for each arm of the people is certainly a fact. Frege uses this equivalence to build numbers. I think Peirce is wrong. If it is not a fact that these people have four eyes, I don't know what 'four' means. It's being two pairs is also a fact. |
| 14770 | Reasoning is based on statistical induction, so it can't achieve certainty or precision [Peirce] |
| Full Idea: All positive reasoning is judging the proportion of something in a whole collection by the proportion found in a sample. Hence we can never hope to attain absolute certainty, absolute exactitude, absolute universality. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], II) | |
| A reaction: This is the basis of Peirce's fallibilism - that all 'positive' reasoning (whatever that it?) is based on statistical induction. I'm all in favour of fallibilism, but find Peirce's claim to be a bit too narrow. He was too mesmerised by physical science. |
| 14774 | Innate truths are very uncertain and full of error, so they certainly have exceptions [Peirce] |
| Full Idea: It seems to me there is the most historic proof that innate truths are particularly uncertain and mixed up with error, and therefore a fortiori not without exception. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], II) |
| 14773 | A truth is hard for us to understand if it rests on nothing but inspiration [Peirce] |
| Full Idea: A truth which rests on the authority of inspiration only is of a somewhat incomprehensible nature; and we can never be sure that we rightly comprehend it. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], II) |
| 14772 | If we decide an idea is inspired, we still can't be sure we have got the idea right [Peirce] |
| Full Idea: Even if we decide that an idea really is inspired, we cannot be sure, or nearly sure, that the statement is true. We know one of the commandments of the Bible was printed without a 'not' in it. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], II) |
| 14771 | Only reason can establish whether some deliverance of revelation really is inspired [Peirce] |
| Full Idea: We never can be absolutely certain that any given deliverance [of revelation] really is inspired; for that can only be established by reasoning. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], II) |
| 14769 | Only imagination can connect phenomena together in a rational way [Peirce] |
| Full Idea: We can stare stupidly at phenomena; but in the absence of imagination they will not connect themselves together in any rational way. | |
| From: Charles Sanders Peirce (Scientific Attitude and Fallibilism [1899], I) | |
| A reaction: The importance of this is its connection between imagination and 'rational' understanding. This is an important corrective to a crude traditional picture of the role of imagination. I would connect imagination with counterfactuals and best explanation. |
| 7604 | Amos was the first prophet to emphasise justice and compassion [Amos, by Armstrong,K] |
| Full Idea: Amos was the first prophet to emphasise social justice and compassion. | |
| From: report of Amos (30: Book of Amos [c.740 BCE]) by Karen Armstrong - A History of God | |
| A reaction: It increasingly strikes me that early religious thinkers were actually working out the rules for good community living, but seeing them through the distorting spectacles of religion as a means to post-life salvation. |