Combining Texts

All the ideas for 'On Motion', 'Philosophy without Intuitions' and 'On the General Idea of Proof Theory'

unexpand these ideas     |    start again     |     specify just one area for these texts


5 ideas

2. Reason / E. Argument / 7. Thought Experiments
So-called 'though experiments' are just philosophers observing features of the world [Cappelen]
     Full Idea: What are called 'thought experiments' in philosophy are in effect just philosophers drawing our attention to interesting features of the world.
     From: Herman Cappelen (Philosophy without Intuitions [2012], 11.3)
     A reaction: Thought experiments are said to rely (perhaps excessively) on 'intuition', but Cappelen says intuition is irrelevant, because we are merely making judgements. It think they ARE experiments, if one feature varies while the rest is held steady.
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Logical consequence isn't a black box (Tarski's approach); we should explain how arguments work [Prawitz]
     Full Idea: Defining logical consequence in the way Tarski does is a rather meagre result, treating an argument as a black box, observing input and output, while disregarding inner structure. We should define logical consequence on the basis of valid arguments.
     From: Dag Prawitz (On the General Idea of Proof Theory [1974], §2)
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory looks at valid sentences and consequence, but not how we know these things [Prawitz]
     Full Idea: In model theory, which has dominated the last decades, one concentrates on logically valid sentences, and what follows logically from what, but one disregards questions concerning how we know these things.
     From: Dag Prawitz (On the General Idea of Proof Theory [1974], §1)
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
The word 'intuitive' often plays not role at all in arguments, and can be removed [Cappelen]
     Full Idea: Careful study of uses of 'intuitive' will reveal that it often plays no significant argumentative role, and that removal will improve overall argumentative transparency.
     From: Herman Cappelen (Philosophy without Intuitions [2012], 04.1)
     A reaction: This is a key part of Cappelen's argument that 'intuition' is a rather empty concept, and that philosophers do not really rely on it. In effect, he is consigning it to mere rhetoric. He gives lots of examples in support.
27. Natural Reality / B. Modern Physics / 1. Relativity / a. Special relativity
Motion is not absolute, but consists in relation [Leibniz]
     Full Idea: In reality motion is not something absolute, but consists in relation.
     From: Gottfried Leibniz (On Motion [1677], A6.4.1968), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 3
     A reaction: It is often thought that motion being relative was invented by Einstein, but Leibniz wholeheartedly embraced 'Galilean relativity', and refused to even consider any absolute concept of motion. Acceleration is a bit trickier than velocity.