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Single Idea 14358
[filed under theme 10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
]
Full Idea
In the possible worlds account modus ponens is validated (the closest world, the actual, is a B-world just if B is true), and modus tollens is validated (if B is false, the actual world is not an A-world, so A is false).
Gist of Idea
In the possible worlds account of conditionals, modus ponens and modus tollens are validated
Source
Frank Jackson (Conditionals [2006], 'Famous')
Book Ref
'Blackwell Guide to Philosophy of Language', ed/tr. Devitt,M/Hanley,R [Blackwell 2006], p.216
A Reaction
[see Jackson for slightly fuller versions] This looks like a minimal requirement for a decent theory of conditionals, so Jackson explains the attractions of the possible worlds view very persuasively.
The
52 ideas
from Frank Jackson
8499
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Nominalists cannot translate 'red resembles pink more than blue' into particulars
[Jackson]
|
8500
|
Colour resemblance isn't just resemblance between things; 'colour' must be mentioned
[Jackson]
|
14288
|
'If A,B' affirms that A⊃B, and also that this wouldn't change if A were certain
[Jackson, by Edgington]
|
13769
|
Conditionals are truth-functional, but should only be asserted when they are confident
[Jackson, by Edgington]
|
14289
|
There are some assertable conditionals one would reject if one learned the antecedent
[Jackson, by Edgington]
|
14353
|
Modus ponens requires that A→B is F when A is T and B is F
[Jackson]
|
14354
|
When A and B have the same truth value, A→B is true, because A→A is a logical truth
[Jackson]
|
14355
|
(A&B)→A is a logical truth, even if antecedent false and consequent true, so it is T if A is F and B is T
[Jackson]
|
14352
|
'¬', '&', and 'v' are truth functions: the truth of the compound is fixed by the truth of the components
[Jackson]
|
14358
|
In the possible worlds account of conditionals, modus ponens and modus tollens are validated
[Jackson]
|
14360
|
Possible worlds for subjunctives (and dispositions), and no-truth for indicatives?
[Jackson]
|
14359
|
Only assertions have truth-values, and conditionals are not proper assertions
[Jackson]
|
14357
|
Possible worlds account, unlike A⊃B, says nothing about when A is false
[Jackson]
|
14356
|
We can't insist that A is relevant to B, as conditionals can express lack of relevance
[Jackson]
|
13858
|
The truth-functional account of conditionals is right, if the antecedent is really acceptable
[Jackson, by Edgington]
|
7880
|
If a blind persons suddenly sees a kestrel, that doesn't make visual and theoretical kestrels different
[Papineau on Jackson]
|
7378
|
No one bothers to imagine what it would really be like to have ALL the physical information
[Dennett on Jackson]
|
7377
|
Mary learns when she sees colour, so her complete physical information had missed something
[Jackson]
|
4894
|
I say Mary does not have new knowledge, but knows an old fact in a new way
[Perry on Jackson]
|
4895
|
Is it unfair that physicalist knowledge can be written down, but dualist knowledge can't be
[Perry on Jackson]
|
4886
|
Mary knows all the physical facts of seeing red, but experiencing it is new knowledge
[Jackson]
|
6976
|
In physicalism, the psychological depends on the physical, not the other way around
[Jackson]
|
6977
|
Egocentric or de se content seems to be irreducibly so
[Jackson]
|
6975
|
Possible worlds could be concrete, abstract, universals, sentences, or properties
[Jackson]
|
7005
|
Something can only have a place in a preferred account of things if it is entailed by the account
[Jackson]
|
6979
|
Serious metaphysics cares about entailment between sentences
[Jackson]
|
6980
|
Conceptual analysis studies whether one story is made true by another story
[Jackson]
|
6982
|
Long arithmetic calculations show the a priori can be fallible
[Jackson]
|
6991
|
We examine objects to determine colour; we do not introspect
[Jackson]
|
6986
|
Is the dependence of the psychological on the physical a priori or a posteriori?
[Jackson]
|
6983
|
Intuitions about possibilities are basic to conceptual analysis
[Jackson]
|
6984
|
Smooth reductions preserve high-level laws in the lower level
[Jackson]
|
6987
|
We should not multiply senses of necessity beyond necessity
[Jackson]
|
6990
|
Keep distinct the essential properties of water, and application conditions for the word 'water'
[Jackson]
|
6985
|
Analysis is finding necessary and sufficient conditions by studying possible cases
[Jackson]
|
6989
|
I can understand "He has a beard", without identifying 'he', and hence the truth conditions
[Jackson]
|
6988
|
Mathematical sentences are a problem in a possible-worlds framework
[Jackson]
|
6993
|
Redness is a property, but only as a presentation to normal humans
[Jackson]
|
6992
|
If different states can fulfil the same role, the converse must also be possible
[Jackson]
|
6998
|
Folk morality does not clearly distinguish between doing and allowing
[Jackson]
|
6997
|
Moral functionalism says moral terms get their meaning from their role in folk morality
[Jackson]
|
7000
|
Which are prior - thin concepts like right, good, ought; or thick concepts like kindness, equity etc.?
[Jackson]
|
6999
|
It is hard to justify the huge difference in our judgements of abortion and infanticide
[Jackson]
|
6995
|
Successful predication supervenes on nature
[Jackson]
|
6994
|
Truth supervenes on being
[Jackson]
|
6996
|
Folk psychology covers input, internal role, and output
[Jackson]
|
6978
|
Baldness is just hair distribution, but the former is indeterminate, unlike the latter
[Jackson]
|
14707
|
Conceptual analysis is needed to establish that metaphysical reductions respect original meanings
[Jackson, by Schroeter]
|
14632
|
Quine may have conflated de re and de dicto essentialism, but there is a real epistemological problem
[Jackson]
|
14631
|
How can you show the necessity of an a posteriori necessity, if it might turn out to be false?
[Jackson]
|
14633
|
How do we tell a table's being contingently plastic from its being essentially plastic?
[Jackson]
|
14635
|
An x is essentially F if it is F in every possible world in which it appears
[Jackson]
|