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16252
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Metaphysics uses empty words, or just produces pseudo-statements [Carnap]
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Full Idea:
Since metaphysics doesn't want to assert analytic propositions, nor fall within the domain of physical science, it is compelled to employ words for which no criteria of application are specified, ..or else combine meaningful words..into pseudo-statements.
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From:
Rudolph Carnap (Elimination of Metaphysics by Analysis of Language [1959]), quoted by Tim Maudlin - The Metaphysics within Physics 2.4
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A reaction:
A classic summary of the logical positivist rejection of metaphysics. I incline to treat metaphysics as within the domain of science, but at a level of generality so high that practising scientists become bewildered and give up.
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5515
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Imaginary cases are good for revealing our beliefs, rather than the truth [Parfit]
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Full Idea:
I believe it is worth considering imaginary cases (such as Teletransportation), as we can use them to discover, not what the truth is, but what we believe.
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From:
Derek Parfit (The Unimportance of Identity [1995], p.293)
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A reaction:
The trouble is that we might say that IF I were suddenly turned into a pig, then I would come to believe in dualism, but that will not and cannot happen, because dualism is false. It seems essential to accept the natural possibility of the case.
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13342
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Carnap defined consequence by contradiction, but this is unintuitive and changes with substitution [Tarski on Carnap]
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Full Idea:
Carnap proposed to define consequence as 'sentence X follows from the sentences K iff the sentences K and the negation of X are contradictory', but 1) this is intuitively impossible, and 2) consequence would be changed by substituting objects.
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From:
comment on Rudolph Carnap (The Logical Syntax of Language [1934], p.88-) by Alfred Tarski - The Concept of Logical Consequence p.414
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A reaction:
This seems to be the first step in the ongoing explicit discussion of the nature of logical consequence, which is now seen by many as the central concept of logic. Tarski brings his new tool of 'satisfaction' to bear.
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13251
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Each person is free to build their own logic, just by specifying a syntax [Carnap]
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Full Idea:
In logic, there are no morals. Everyone is at liberty to build his own logic, i.e. his own form of language. All that is required is that he must state his methods clearly, and give syntactical rules instead of philosophical arguments.
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From:
Rudolph Carnap (The Logical Syntax of Language [1934], §17), quoted by JC Beall / G Restall - Logical Pluralism 7.3
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A reaction:
This is understandable, but strikes me as close to daft relativism. If I specify a silly logic, I presume its silliness will be obvious. By what criteria? I say the world dictates the true logic, but this is a minority view.
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8748
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Logical positivists incorporated geometry into logicism, saying axioms are just definitions [Carnap, by Shapiro]
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Full Idea:
The logical positivists brought geometry into the fold of logicism. The axioms of, say, Euclidean geometry are simply definitions of primitive terms like 'point' and 'line'.
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From:
report of Rudolph Carnap (Empiricism, Semantics and Ontology [1950]) by Stewart Shapiro - Thinking About Mathematics 5.3
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A reaction:
If the concept of 'line' is actually created by its definition, then we need to know exactly what (say) 'shortest' means. If we are merely describing a line, then our definition can be 'impredicative', using other accepted concepts.
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5516
|
Reduction can be by identity, or constitution, or elimination [Parfit, by PG]
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Full Idea:
We can distinguish Identifying Reductionism (as in 'persons are bodies'), or Constitutive Reductionism (as in 'persons are distinct, but consist of thoughts etc.'), or Eliminative Reductionism (as in 'there are no persons, only thoughts etc.').
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From:
report of Derek Parfit (The Unimportance of Identity [1995], p.295) by PG - Db (ideas)
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A reaction:
Constitutive Reductionism seems the most common one, as in 'chemistry just consists of lots of complicated physics'. He doesn't mention bridge laws, which are presumably only required in more complicated cases of constitutive reduction.
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13933
|
Existence questions are 'internal' (within a framework) or 'external' (concerning the whole framework) [Carnap]
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Full Idea:
We distinguish two kinds of existence questions: first, entities of a new kind within the framework; we call them 'internal questions'. Second, 'external questions', concerning the existence or reality of the system of entities as a whole.
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From:
Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 2)
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A reaction:
This nicely disposes of many ontological difficulties, but at the price of labelling most external questions as meaningless, so that the internal answers have very little commitment, and the external (big) questions are now banned. Not for me.
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13935
|
We only accept 'things' within a language with formation, testing and acceptance rules [Carnap]
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Full Idea:
To accept the thing world means nothing more than to accept a certain form of language, in other words, to accept rules for forming statements and for testing, accepting, or rejecting them.
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From:
Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 2)
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A reaction:
If you derive your metaphysics from your language, then objects are linguistic conventions. But why do we accept conventions about objects?
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14305
|
In the truth-functional account a burnt-up match was soluble because it never entered water [Carnap]
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Full Idea:
If a wooden match was completely burned up yesterday, and never placed in water at any time, is it not the case, therefore, that the match is soluble (in the truth-functional view). This follows just from the antecedent being false.
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From:
Rudolph Carnap (Testability and Meaning [1937], I.440), quoted by Stephen Mumford - Dispositions
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A reaction:
This, along with Edgington's nice example of the conditional command (Idea ) seems conclusive against the truth-functional account. The only defence possible is some sort of pragmatic account about implicature.
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13932
|
Empiricists tend to reject abstract entities, and to feel sympathy with nominalism [Carnap]
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Full Idea:
Empiricists are in general rather suspicious with respect to any kind of abstract entities like properties, classes, relations, numbers, propositions etc. They usually feel more sympathy with nominalists than with realists (in the medieval sense).
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From:
Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 1)
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A reaction:
The obvious reason is that you can't have sense experiences of abstract entities. I like the question 'what are they made of?' rather than the question 'how can I experience them?'.
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13937
|
New linguistic claims about entities are not true or false, but just expedient, fruitful or successful [Carnap]
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Full Idea:
The acceptance of new linguistic forms about entities cannot be judged as being either true or false because it is not an assertion. It can only be judged as being more or less expedient, fruitful, conducive to the aim for which the language is intended.
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From:
Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 3)
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A reaction:
The obvious problem seems to be that a complete pack of lies might be successful for a very long time, if it plugged a critical hole in a major theory. Is success judged financially? How do we judge success without mentioning truth?
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13048
|
Good explications are exact, fruitful, simple and similar to the explicandum [Carnap, by Salmon]
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Full Idea:
Carnap's four criteria for giving a good explication are similarity to the explicandum, exactness, fruitfulness and simplicity.
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From:
report of Rudolph Carnap (Logical Foundations of Probability [1950], Ch.1) by Wesley Salmon - Four Decades of Scientific Explanation 0.1
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A reaction:
[compressed] Salmon's view is that this represents the old attitude, that the contribution of philosophy to explanation is the clarification of the key concepts. Carnap is, of course, a logical empiricist.
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5514
|
Psychologists are interested in identity as a type of person, but philosophers study numerical identity [Parfit]
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Full Idea:
When psychologists discuss identity, they are typically concerned with the kind of person someone is, or wants to be (as in an 'identity crisis'). But when philosophers discuss identity, it is numerical identity they mean.
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From:
Derek Parfit (The Unimportance of Identity [1995], p.293)
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A reaction:
I think it is important to note that the philosophical problem breaks down into two areas: whether I have numerical identity with myself over time, and whether other people have it. It may be that two different sets of criteria will emerge.
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5521
|
If my brain-halves are transplanted into two bodies, I have continuity, and don't need identity [Parfit]
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Full Idea:
If the two halves of my brain are transplanted into different bodies just like mine, they cannot both be me, since that would make them the same person. ..But my relation to these two contains everything that matters, so identity is not what matters.
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From:
Derek Parfit (The Unimportance of Identity [1995], p.314)
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A reaction:
I challenge his concept of what 'matters'. He has a rather solipsistic view of the problem, and I take Parfit to be a rather unsociable person, since his friends and partner will be keenly interested in the identities of the new beings.
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1392
|
If we split like amoeba, we would be two people, neither of them being us [Parfit]
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Full Idea:
In the case of the man who, like an amoeba, divides….we can suggest that he survives as two different people without implying that he is those people.
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From:
Derek Parfit (Personal Identity [1971], §1)
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A reaction:
Maybe an amoeba is a homogeneous substance for which splitting is insignificant, but when a person has certain parts that are totally crucial, splitting them is catastrophic, and quite different. I'm not sure that splitting a self would leave persons.
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5519
|
It is fine to save two dying twins by merging parts of their bodies into one, and identity is irrelevant [Parfit]
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Full Idea:
If I am largely paralysed, and my twin brother is dying of brain disease, then if the operation to graft my head onto his body is offered, I should accept the operation, and it is irrelevant whether this person would be me.
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From:
Derek Parfit (The Unimportance of Identity [1995], p.308)
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A reaction:
Parfit notes that the brain is a particularly significant part of the process. The fact that I might cheerfully accept this offer without philosophical worries doesn't get rid of the question 'who is this person?' Who should they remain married to?
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5520
|
If two humans are merged surgically, the new identity is a purely verbal problem [Parfit]
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Full Idea:
If there is someone with my head and my brother's body, it is a merely verbal question whether that person will be me, and that is why, even if it won't be me, that doesn't matter. ..What matters is not identity, but the facts of which identity consists.
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From:
Derek Parfit (The Unimportance of Identity [1995], p.310)
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A reaction:
It strikes me that from the subjective psychological point of view identity is of little interest, but from the objective external viewpoint (e.g. the forensic one) such questions are highly significant, and rightly so.
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1391
|
Concern for our own lives isn't the source of belief in identity, it is the result of it [Parfit]
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Full Idea:
Egoism, and the fear not of near but of distant death, and the regret that so much of one's life should have gone by - these are not, I think, wholly natural or instinctive. They are strengthened by a false belief in stable identity.
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From:
Derek Parfit (Personal Identity [1971], §6)
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A reaction:
This raises some very nice questions, about the extent to which various aspects of self-concern are instinctive and natural, or culturally induced, and even totally misguided and false. I can worry about the distant death of my guinea pig, or my grandson.
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9762
|
We should focus less on subjects of experience, and more on the experiences themselves [Parfit]
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Full Idea:
It becomes more plausible, when thinking morally, to focus less upon the person, the subject of experiences, and instead to focus more upon the experiences themselves.
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From:
Derek Parfit (Reasons and Persons [1984], §116)
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A reaction:
This pinpoints how Parfit moves from a view of persons in terms of continuity of consciousness to a utilitarian morality. It brings out nicely what is wrong with utilitarianism - the reductio of a great ball of nice experiences, with no one having them.
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