Combining Texts

All the ideas for 'The Logic of Boundaryless Concepts', 'The Thought: a Logical Enquiry' and 'Thought: a very short introduction'

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21 ideas

2. Reason / A. Nature of Reason / 5. Objectivity
There exists a realm, beyond objects and ideas, of non-spatio-temporal thoughts [Frege, by Weiner]
     Full Idea: There is, in addition to the external world of physical objects and the internal world of ideas, a third realm of non-spatio-temporal objective objects, among which are thoughts.
     From: report of Gottlob Frege (The Thought: a Logical Enquiry [1918]) by Joan Weiner - Frege Ch.7
     A reaction: This seems to be Platonism, and, in particular, to give a Platonic existent status to propositions. Personally I believe in propositions, but as glimpses of how our brains actually work, not as mystical objects.
3. Truth / A. Truth Problems / 2. Defining Truth
The word 'true' seems to be unique and indefinable [Frege]
     Full Idea: It seems likely that the content of the word 'true' is sui generis and indefinable
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.327 (60))
     A reaction: This is the view I associate with Davidson, though fans of Axiomatic Truth give up defining it, and just describe how it behaves. Defining it is very elusive, but I don't accept that nothing can be said about the contents of the concept of truth.
3. Truth / C. Correspondence Truth / 3. Correspondence Truth critique
There cannot be complete correspondence, because ideas and reality are quite different [Frege]
     Full Idea: It is essential that the reality shall be distinct from the idea. But then there can be no complete correspondence, no complete truth.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.327 (60))
     A reaction: He thinks that logic can give a perfect account of truth, or at least the extension of truth, where ordinary language will always fail. I wonder what he would have thought of Tarski's theory?
3. Truth / H. Deflationary Truth / 1. Redundant Truth
The property of truth in 'It is true that I smell violets' adds nothing to 'I smell violets' [Frege]
     Full Idea: The sentence 'I smell the scent of violets' has just the same content as 'It is true that I smell the scent of violets'. So it seems that nothing is added to the thought by my ascribing to it the property of truth.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.328 (61))
     A reaction: This idea predates Ramsey's similar proposal, for which, oddly, Ramsey always seems to get the credit. To a logician they may have identical content, but pragmatically they are likely to differ in context. 'True' certainly doesn't add to the thought.
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Logic guides thinking, but it isn't a substitute for it [Rumfitt]
     Full Idea: Logic is part of a normative theory of thinking, not a substitute for thinking.
     From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.13)
     A reaction: There is some sort of logicians' dream, going back to Leibniz, of a reasoning engine, which accepts propositions and outputs inferences. I agree with this idea. People who excel at logic are often, it seems to me, modest at philosophy.
7. Existence / A. Nature of Existence / 2. Types of Existence
Thoughts in the 'third realm' cannot be sensed, and do not need an owner to exist [Frege]
     Full Idea: Thoughts are neither things in the external world nor ideas. A third realm must be recognised. Anything in this realm has it in common with ideas that it cannot be perceived by the senses, and does not need an owner to belong with his consciousness.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.337(69))
     A reaction: This important idea is the creed for modern platonists. We don't have to accept Forms, or any particular content, but there is a mode of existence which is distinct from both mental and physical, and is the residence of 'abstracta'. I deny it!
7. Existence / D. Theories of Reality / 8. Facts / c. Facts and truths
A fact is a thought that is true [Frege]
     Full Idea: A fact is a thought that is true.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.342(74))
     A reaction: It strikes me as pretty obvious that facts are not thoughts, because they concern the contents of thoughts. You can't discuss facts without the notion of what a thought is 'about'. If I think about my garden, the relevant fact is aspects of my garden.
9. Objects / A. Existence of Objects / 3. Objects in Thought
Late Frege saw his non-actual objective objects as exclusively thoughts and senses [Frege, by Dummett]
     Full Idea: Earlier, Frege divided objects into subjective, actual objective, and non-actual objective; in the 'Grundgesetze' he emphasised logical objects; but in 'The Thought' the non-actual objects become exclusively thoughts and their constituent senses.
     From: report of Gottlob Frege (The Thought: a Logical Enquiry [1918]) by Michael Dummett - Frege philosophy of mathematics Ch.18
     A reaction: Sounds to me like Frege was finally waking up and taking a dose of common sense. The Equator is the standard example of a non-actual objective object.
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
Vague membership of sets is possible if the set is defined by its concept, not its members [Rumfitt]
     Full Idea: Vagueness in respect of membership is consistency with determinacy of the set's identity, so long as a set's identity is taken to consist, not in its having such-and-such members, but in its being the extension of a concept.
     From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.5)
     A reaction: I find this view of sets much more appealing than the one that identifies a set with its members. The empty set is less of a problem, as well as non-existents. Logicians prefer the extensional view because it is tidy.
13. Knowledge Criteria / B. Internal Justification / 3. Evidentialism / a. Evidence
How we evaluate evidence depends on our background beliefs [Bayne]
     Full Idea: A claim that might be very plausible given one set of background beliefs might be highly implausible when evaluated in the light of a different set of background beliefs.
     From: Tim Bayne (Thought: a very short introduction [2013], Ch.7)
Clifford's dictum seems to block our beliefs in morality, politics and philosophy [Bayne]
     Full Idea: Endorsing Clifford's dictum threatens to undermine our right to hold many of our most cherished beliefs about morality, politics, and philosophy, for these are domains in which it is notoriously difficult to secure consensus.
     From: Tim Bayne (Thought: a very short introduction [2013], Ch.7)
     A reaction: I would say that those beliefs are amenable to evidence, but the evidence is often highly generalised, which is what makes those subjects notoriously difficult. The existence of a convention is a sort of evidence.
17. Mind and Body / E. Mind as Physical / 1. Physical Mind
Physicalism correlates brain and mind, explains causation by thought, and makes nature continuous [Bayne]
     Full Idea: The motivations for physicalism about the mind are that it accounts for correlations between states of the brain and states of thought, ...that it accounts for the causal role of thoughts, ...and that it does justice to the continuity of nature.
     From: Tim Bayne (Thought: a very short introduction [2013], Ch.2)
     A reaction: [summary] That is a pretty good summary of why I am a physicalist about the mind. I take all other theories to be dead footnotes in the history of thought - unless someone can produce a really good new argument. Which they can't.
18. Thought / A. Modes of Thought / 1. Thought
We grasp thoughts (thinking), decide they are true (judgement), and manifest the judgement (assertion) [Frege]
     Full Idea: We distinguish the grasp of a thought, which is 'thinking', from the acknowledgement of the truth of a thought, which is the act of 'judgement', from the manifestation of this judgement, which is an 'assertion'.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.329 (62))
Thoughts have their own realm of reality - 'sense' (as opposed to the realm of 'reference') [Frege, by Dummett]
     Full Idea: For Frege, thoughts belong to a special realm of reality, which he called the 'realm of sense' and distinguished from the 'realm of reference'.
     From: report of Gottlob Frege (The Thought: a Logical Enquiry [1918]) by Michael Dummett - Thought and Reality 1
     A reaction: A thought is, for Frege, a proposition. There is a halfway Platonism possible here, where the 'realm' for such things exists, but within that realm the objects might be conventional, or some such. Real possible worlds containing fictions!
A thought is distinguished from other things by a capacity to be true or false [Frege, by Dummett]
     Full Idea: On Frege's view, what distinguishes thoughts from everything else is that they may meaningfully be called 'true' and 'false'.
     From: report of Gottlob Frege (The Thought: a Logical Enquiry [1918]) by Michael Dummett - Frege philosophy of mathematics Ch.2
     A reaction: A lot of thinking is imagistic, and while the image may or may not truly picture the world, we tend to think that the truth or otherwise of daydreaming is simply irrelevant. Does Frege take all thought to be propositional?
18. Thought / A. Modes of Thought / 8. Human Thought
Perception reveals what animals think, but humans can disengage thought from perception [Bayne]
     Full Idea: One striking feature of human thought involves our ability to disengage the focus of thought from that of our perceptual attention. ...To get a fix on what an animal is thinking about, one need only determine the object of its perceptual attention.
     From: Tim Bayne (Thought: a very short introduction [2013], Ch.4)
     A reaction: What happens when an animal closes its eyes, or stirs violently during sleep? I take the hallmark of human thought to be its multi-level character, and this offers nice evidence for that view. Doing philosophy while driving a car is very revealing.
Some people centre space on themselves; others centre space on the earth [Bayne]
     Full Idea: Egocentric conceptions of space employ a frame of reference that is focused on oneself; ...geocentric conceptions of space, by contrast, employ a frame of reference that is centred on the earth.
     From: Tim Bayne (Thought: a very short introduction [2013], Ch.5)
     A reaction: Famously, Europeans nearly always employ the egocentric conception, but many other cultures are geocentric. Thus the salt cellar is either 'to my left' or 'to the west'. In the latter view, everyone always knows their orientation (even indoors?).
18. Thought / A. Modes of Thought / 9. Indexical Thought
Thoughts about myself are understood one way to me, and another when communicated [Frege]
     Full Idea: When Dr Lauben thinks he has been wounded, ..only Dr Lauben can grasp thoughts determined in this way. But he cannot communicate a thought which only he can grasp. To say 'I have been wounded' he must use 'I' in a sense graspable by others.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918]), quoted by François Recanati - Mental Files 16.1
     A reaction: [compressed] This seems to be the first, and very influential, attempt to explain the unusual and revealing semantics of indexicals. It seems to be the ultimate source of 2-D semantics, by introducing two modes of meaning for one term.
18. Thought / B. Mechanics of Thought / 4. Language of Thought
The alternative to a language of thought is map-like or diagram-like thought [Bayne]
     Full Idea: One could think that the structure of thought has more in common with that of maps or diagrams, and is not particularly language-like.
     From: Tim Bayne (Thought: a very short introduction [2013], Ch.2)
     A reaction: It seems unwise to be ensnared by analogies on this one, since the phenomenon is buried deep. You can no more infer what goes on underneath than you can infer electrons from looking at trees?
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
A 'thought' is something for which the question of truth can arise; thoughts are senses of sentences [Frege]
     Full Idea: I call a 'thought' something for which the question of truth can arise at all. ...So I can say: thoughts are senses of sentences, without wishing to assert that the sense of every sentence is a thought.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.327-8 (61))
     A reaction: This builds on his distinction between sense and reference. The reference of every truth sentence is just 'the true', and the sense is the proposition. The concept of a proposition seems indispensable to logic, I would say.
19. Language / D. Propositions / 5. Unity of Propositions
A sentence is only a thought if it is complete, and has a time-specification [Frege]
     Full Idea: Only a sentence with the time-specification filled out, a sentence complete in every respect, expresses a thought.
     From: Gottlob Frege (The Thought: a Logical Enquiry [1918], p.343(76))
     A reaction: I take the 'every respect' to include the avoidance of ambiguity, and some sort of perspicacious reference for the terms. I wish philosophers would focus on the thoughts in their subject, and not nit-pick about the sentences. Does he mean 'utterances'?