7 ideas
| 17990 | Instances of minimal truth miss out propositions inexpressible in current English [Hofweber] |
| Full Idea: A standard objection to minimalist truth is the 'incompleteness objection'. Since there are propositions inexpressible in present English the concept of truth isn't captured by all the instances of the Tarski biconditional. | |
| From: Thomas Hofweber (Inexpressible Properties and Propositions [2006], 5.3) | |
| A reaction: Sounds like a good objection. |
| 17743 | De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things' [De Morgan, by Walicki] |
| Full Idea: In 1846 De Morgan introduced the enormously influential notion of a possibly arbitrary and stipulated 'universe of discourse'. It replaced Boole's original - and metaphysically a bit suspect - universe of 'all things'. | |
| From: report of Augustus De Morgan (works [1846]) by Michal Walicki - Introduction to Mathematical Logic History D.1.1 | |
| A reaction: This not only brings formal logic under control, but also reflects normal talk, because there is always an explicit or implicit domain of discourse when we talk. Of virtually any conversation, you can say what it is 'about'. |
| 17988 | Quantification can't all be substitutional; some reference is obviously to objects [Hofweber] |
| Full Idea: The view that all quantification is substitutional is not very plausible in general. Some uses of quantifiers clearly seem to have the function to make a claim about a domain of objects out there, no matter how they relate to the terms in our language. | |
| From: Thomas Hofweber (Inexpressible Properties and Propositions [2006], 2.1) | |
| A reaction: Robust realists like myself are hardly going to say that quantification is just an internal language game. |
| 18085 | Values that approach zero, becoming less than any quantity, are 'infinitesimals' [Cauchy] |
| Full Idea: When the successive absolute values of a variable decrease indefinitely in such a way as to become less than any given quantity, that variable becomes what is called an 'infinitesimal'. Such a variable has zero as its limit. | |
| From: Augustin-Louis Cauchy (Cours d'Analyse [1821], p.19), quoted by Philip Kitcher - The Nature of Mathematical Knowledge 10.4 | |
| A reaction: The creator of the important idea of the limit still talked in terms of infinitesimals. In the next generation the limit took over completely. |
| 18084 | When successive variable values approach a fixed value, that is its 'limit' [Cauchy] |
| Full Idea: When the values successively attributed to the same variable approach indefinitely a fixed value, eventually differing from it by as little as one could wish, that fixed value is called the 'limit' of all the others. | |
| From: Augustin-Louis Cauchy (Cours d'Analyse [1821], p.19), quoted by Philip Kitcher - The Nature of Mathematical Knowledge 10.4 | |
| A reaction: This seems to be a highly significan proposal, because you can now treat that limit as a number, and adds things to it. It opens the door to Cantor's infinities. Is the 'limit' just a fiction? |
| 17989 | Since properties have properties, there can be a typed or a type-free theory of them [Hofweber] |
| Full Idea: Since properties themselves can have properties there is a well-known division in the theory of properties between those who take a typed and those who take a type-free approach. | |
| From: Thomas Hofweber (Inexpressible Properties and Propositions [2006], 2.2) | |
| A reaction: A typed approach would imply restrictions on what it can be a property of. 'Green' is a property of surfaces, 'dark' is a property of colours. My first reaction is to opt for type-free. |
| 17991 | Holism says language can't be translated; the expressibility hypothesis says everything can [Hofweber] |
| Full Idea: Holism says that nothing that can be said in one language can be said in another one. The expressibility hypothesis says that everything that can be said in one language can be said in every other one. | |
| From: Thomas Hofweber (Inexpressible Properties and Propositions [2006], 6.4) | |
| A reaction: Obviously expressibility would only refer to reasonably comprehensive languages (with basic logical connectives, for example). Personally I vote for the expressibility hypothesis, which Hofweber seems to favour. |