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16908
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We can dispense with self-evidence, if language itself prevents logical mistakes [Jeshion on Wittgenstein]
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Full Idea:
The 'self-evidence' of which Russell talks so much can only be dispensed with in logic if language itself prevents any logical mistake.
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From:
comment on Ludwig Wittgenstein (Notebooks 1914-1916 [1915], 4) by Robin Jeshion - Frege's Notion of Self-Evidence 4
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A reaction:
Jeshion presents this as a key idea, turning against Frege, and is the real source of the 'linguistic turn' in philosophy. If self-evidence is abandoned, then language itself is the guide to truth, so study language. I think I prefer Frege. See Quine?
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6563
|
'And' and 'not' are non-referring terms, which do not represent anything [Wittgenstein, by Fogelin]
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Full Idea:
Wittgenstein's 'fundamental idea' is that the 'and' and 'not' which guarantee the truth of "not p and not-p" are meaningful, but do not get their meaning by representing or standing for or referring to some kind of entity; they are non-referring terms.
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From:
report of Ludwig Wittgenstein (Notebooks 1914-1916 [1915], §37) by Robert Fogelin - Walking the Tightrope of Reason Ch.1
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A reaction:
Wittgenstein then defines the terms using truth tables, to show what they do, rather than what they stand for. This seems to me to be a candidate for the single most important idea in the history of the philosophy of logic.
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16744
|
All powers can be explained by obvious features like size, shape and motion of matter [Descartes]
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Full Idea:
There are no powers in stones and plants that are not so mysterious that they cannot be explained …from principles that are known to all and admitted by all, namely the shape, size, position, and motion of particles of matter.
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|
From:
René Descartes (Principles of Philosophy [1646], IV.187), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 23.6
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A reaction:
This is an invocation of 'categorical' properties, against dispositions. I take this to be quite wrong. The explanation goes the other way. What supports the structures; what drives the motion; what initiates anything?
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5016
|
Five universals: genus, species, difference, property, accident [Descartes]
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Full Idea:
The five commonly enumerated universals are: genus, species, difference, property and accident.
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From:
René Descartes (Principles of Philosophy [1646], I.59)
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A reaction:
Interestingly, this seems to be Descartes passing on his medieval Aristotelian inheritance, in which things are defined by placing them in a class, and then noting what distinguishes them within that class.
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16633
|
A substance has one principal property which is its nature and essence [Descartes]
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Full Idea:
Each substance has one principal property that constitutes its nature and essence, to which all its other properties are referred. Extension in length, breadth, and depth constitutes the nature of corporeal substance; and thought of thinking substances.
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|
From:
René Descartes (Principles of Philosophy [1646], I.53), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 08.3
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A reaction:
Property is likely to be 'propria', which is a property distinctive of some thing, not just any old modern property. This is quite a strikingly original view of the nature of essence. Descartes despised 'substantial forms'.
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5005
|
I think, therefore I am, because for a thinking thing to not exist is a contradiction [Descartes]
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Full Idea:
There is a contradiction in conceiving that what thinks does not (at the same time as it thinks) exist. Hence this conclusion I think, therefore I am, is the first and most certain that occurs to one who philosophises in an orderly way.
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|
From:
René Descartes (Principles of Philosophy [1646], I.07)
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A reaction:
The classic statement of his argument. The significance here is that it seems to have the structure of an argument, as it involves 'philosophising', which leads to a 'contradiction', and hence to the famous conclusion. It is not just intuitive.
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5006
|
'Thought' is all our conscious awareness, including feeling as well as understanding [Descartes]
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Full Idea:
By the word 'thought' I understand everything we are conscious of as operating in us. And that is why not only understanding, willing, imagining, but also feeling, are here the same thing as thinking.
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|
From:
René Descartes (Principles of Philosophy [1646], I.09)
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|
A reaction:
There is a bit of tension here between Descartes' correct need to include feeling in thought for his Cogito argument, and his tendency to dismiss animal consciousness, on the grounds that they only sense things, and don't make judgements.
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|
5012
|
'Nothing comes from nothing' is an eternal truth found within the mind [Descartes]
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|
Full Idea:
The proposition 'nothing comes from nothing' is not to be considered as an existing thing, or the mode of a thing, but as a certain eternal truth which has its seat in our mind and is a common notion or axiom.
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|
From:
René Descartes (Principles of Philosophy [1646], I.49)
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|
A reaction:
There is a tension here, in his assertion that it is 'eternal', but 'not existing'. How does one distinguish an innate idea from an innate truth? 'Eternal' sounds like an external guarantee of truth, but being 'in our mind' sounds less reliable.
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|
5004
|
We can know basic Principles without further knowledge, but not the other way round [Descartes]
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|
Full Idea:
It is on the Principles, or first causes, that the knowledge of other things depends, so the Principles can be known without these last, but the other things cannot reciprocally be known without the Principles.
|
|
From:
René Descartes (Principles of Philosophy [1646], Pref)
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|
A reaction:
A particularly strong assertion of foundationalism, as it says that not only must the foundations exist, but also we must actually know them. This sounds false, as elementary knowledge then seems to require far too much sophistication.
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22323
|
The philosophical I is the metaphysical subject, the limit - not a part of the world [Wittgenstein]
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|
Full Idea:
The philosophical I is not the man, not the human body, or the human soul of wh9ch psychology treats, but the metaphysical subject, the limit - not a part of the world.
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|
From:
Ludwig Wittgenstein (Notebooks 1914-1916 [1915], 1916. 2 Sep), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 58 Intro
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|
A reaction:
This is to treat the self as a phenomenon of thought, rather than of a human being. So if a machine could think, would it hence necessarily have a metaphysical self?
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|
5011
|
There are two ultimate classes of existence: thinking substance and extended substance [Descartes]
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|
Full Idea:
I observe two ultimate classes of things: intellectual or thinking things, pertaining to the mind or to thinking substance, and material things, pertaining to extended substance or to body.
|
|
From:
René Descartes (Principles of Philosophy [1646], I.48)
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|
A reaction:
This is clear confirmation that Descartes believed the mind is a substance, rather than an insubstantial world of thinking. It leaves open the possibility of a different theory: that mind is not a substance, but is a Platonic adjunct to reality.
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|
5018
|
Even if tightly united, mind and body are different, as God could separate them [Descartes]
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|
Full Idea:
Even if we suppose God had united a body and a soul so closely that they couldn't be closer, and made a single thing out of the two, they would still remain distinct, because God has the power of separating them, or conserving out without the other.
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|
From:
René Descartes (Principles of Philosophy [1646], I.60)
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|
A reaction:
If Descartes lost his belief in God (after discussing existence with Kant) would he cease to be a dualist? This quotation seems to be close to conceding a mind-body relationship more like supervenience than interaction.
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|
5008
|
The greatest perfection of man is to act by free will, and thus merit praise or blame [Descartes]
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|
Full Idea:
That the will should extend widely accords with its nature, and it is the greatest perfection in man to be able to act by its means, that is, freely, and by so doing we are in peculiar way masters of our actions, and thereby merit praise or blame.
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|
From:
René Descartes (Principles of Philosophy [1646], I.37)
|
|
A reaction:
This seems to me to be a deep-rooted and false understanding which philosophy has inherited from theology. It doesn't strike me that there must an absolute 'buck-stop' to make us responsible. Why is it better for a decision to appear out of nowhere?
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|
4678
|
Absolute prohibitions are the essence of ethics, and suicide is the most obvious example [Wittgenstein]
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|
Full Idea:
If suicide is allowed, then everything is allowed. If anything is not allowed, then suicide is not allowed. This throws a light on the nature of ethics, for suicide is, so to speak, the elementary sin.
|
|
From:
Ludwig Wittgenstein (Notebooks 1914-1916 [1915], end), quoted by Jonathan Glover - Causing Death and Saving Lives §13
|
|
A reaction:
This reveals the religious streak in Wittgenstein. I am reluctant to judge suicide, but this seems wrong. Should a 'jumper' worry if they land on someone else and kill them? Of course they should.
|
|
15987
|
Physics only needs geometry or abstract mathematics, which can explain and demonstrate everything [Descartes]
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|
Full Idea:
I do not accept or desire any other principle in physics than in geometry or abstract mathematics, because all the phenomena of nature may be explained by their means, and sure demonstrations can be given of them.
|
|
From:
René Descartes (Principles of Philosophy [1646], 2.64), quoted by Peter Alexander - Ideas, Qualities and Corpuscles 7
|
|
A reaction:
This is his famous and rather extreme view, which might be described as hyper-pythagoreanism (by adding geometry to numbers). It seems to leave out matter, forces and activity.
|
|
16601
|
Matter is not hard, heavy or coloured, but merely extended in space [Descartes]
|
|
Full Idea:
The nature of matter, or body viewed as a whole, consists not in its being something which is hard, heavy, or colored, or which in any other way affects the senses, but only in its being a thing extended in length, breadth and depth.
|
|
From:
René Descartes (Principles of Philosophy [1646], 2.4), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 04.5
|