12 ideas
| 10153 | In everyday language, truth seems indefinable, inconsistent, and illogical [Tarski] |
| Full Idea: In everyday language it seems impossible to define the notion of truth or even to use this notion in a consistent manner and in agreement with the laws of logic. | |
| From: Alfred Tarski (works [1936]), quoted by Feferman / Feferman - Alfred Tarski: life and logic Int III | |
| A reaction: [1935] See Logic|Theory of Logic|Semantics of Logic for Tarski's approach to truth. |
| 19141 | Tarski thought axiomatic truth was too contingent, and in danger of inconsistencies [Tarski, by Davidson] |
| Full Idea: Tarski preferred an explicit definition of truth to axioms. He says axioms have a rather accidental character, only a definition can guarantee the continued consistency of the system, and it keeps truth in harmony with physical science and physicalism. | |
| From: report of Alfred Tarski (works [1936]) by Donald Davidson - Truth and Predication 2 n2 | |
| A reaction: Davidson's summary, gleaned from various sources in Tarski. A big challenge for modern axiom systems is to avoid inconsistency, which is extremely hard to do (given that set theory is not sure of having achieved it). |
| 10048 | There is no clear boundary between the logical and the non-logical [Tarski] |
| Full Idea: No objective grounds are known to me which permit us to draw a sharp boundary between the two groups of terms, the logical and the non-logical. | |
| From: Alfred Tarski (works [1936]), quoted by Alan Musgrave - Logicism Revisited §3 | |
| A reaction: Musgrave is pointing out that this is bad news if you want to 'reduce' something like arithmetic to logic. 'Logic' is a vague object. |
| 10479 | Logical consequence: true premises give true conclusions under all interpretations [Tarski, by Hodges,W] |
| Full Idea: Tarski's definition of logical consequence (1936) is that in a fully interpreted formal language an argument is valid iff under any allowed interpretation of its nonlogical symbols, if the premises are true then so is the conclusion. | |
| From: report of Alfred Tarski (works [1936]) by Wilfrid Hodges - Model Theory 3 | |
| A reaction: The idea that you can only make these claims 'under an interpretation' seems to have had a huge influence on later philosophical thinking. |
| 10694 | Logical consequence is when in any model in which the premises are true, the conclusion is true [Tarski, by Beall/Restall] |
| Full Idea: Tarski's 1936 definition of logical consequence is that in any model in which the premises are true, the conclusion is true too (so that no model can make the conclusion false). | |
| From: report of Alfred Tarski (works [1936]) by JC Beall / G Restall - Logical Consequence 3 | |
| A reaction: So the general idea is that a logical consequence is distinguished by being unstoppable. Sounds good. But then we have monotonic and non-monotonic logics, which (I'm guessing) embody different notions of consequence. |
| 17435 | Objects do not naturally form countable units [Koslicki] |
| Full Idea: Objects do not by themselves naturally fall into countable units. | |
| From: Kathrin Koslicki (Isolation and Non-arbitrary Division [1997], 2.2) | |
| A reaction: Hm. This seems to be modern Fregean orthodoxy. Why did the institution of counting ever get started if the things in the world didn't demand counting? Even birds are aware of the number of eggs in their nest (because they miss a stolen one). |
| 17433 | We can still count squares, even if they overlap [Koslicki] |
| Full Idea: The fact that there is overlap does not seem to inhibit our ability to count squares. | |
| From: Kathrin Koslicki (Isolation and Non-arbitrary Division [1997], 2.2) | |
| A reaction: She has a diagram of three squares overlapping slightly at their corners. Contrary to Frege, these seems to depend on a subliminal concept of the square that doesn't depend on language. |
| 17439 | There is no deep reason why we count carrots but not asparagus [Koslicki] |
| Full Idea: Why do speakers of English count carrots but not asparagus? There is no 'deep' reason. | |
| From: Kathrin Koslicki (Isolation and Non-arbitrary Division [1997]) | |
| A reaction: Koslick is offering this to defend the Fregean conceptual view of counting, but what seems to matter is what is countable, and not whether we happen to count it. You don't need to know what carrots are to count them. Cooks count asparagus. |
| 17434 | We struggle to count branches and waves because our concepts lack clear boundaries [Koslicki] |
| Full Idea: The reason we have a hard time counting the branches and the waves is because our concepts 'branches on the tree' and 'waves on the ocean' do not determine sufficiently precise boundaries: the concepts do not draw a clear invisible line around each thing. | |
| From: Kathrin Koslicki (Isolation and Non-arbitrary Division [1997], 2.2) | |
| A reaction: This is the 'isolation' referred to in Frege. |
| 10157 | Tarski improved Hilbert's geometry axioms, and without set-theory [Tarski, by Feferman/Feferman] |
| Full Idea: Tarski found an elegant new axiom system for Euclidean geometry that improved Hilbert's earlier version - and he formulated it without the use of set-theoretical notions. | |
| From: report of Alfred Tarski (works [1936]) by Feferman / Feferman - Alfred Tarski: life and logic Ch.9 |
| 17436 | We talk of snow as what stays the same, when it is a heap or drift or expanse [Koslicki] |
| Full Idea: Talk of snow concerns what stays the same when some snow changes, as it might be, from a heap of snow to a drift, to an expanse. | |
| From: Kathrin Koslicki (Isolation and Non-arbitrary Division [1997], 2.2) | |
| A reaction: The whiteness also stays the same, but isn't stuff. |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom. | |
| From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88) | |
| A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate'). |