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Ideas of Thomas Aquinas, by Text

[Italian, 1225 - 1274, Born Roccasecca, Italy. Dominican monk. Taught by Albertus Magnus. Based Paris, then Italy. Died at Fossanova. 'Doctor Angelicus'.]

1264 Sentences
IV.13.2.3sc p.433 Heretics should be eradicated like wolves
     Full Idea: Heretics are wolves …and therefore ought to be eradicated.
     From: Thomas Aquinas (Sentences [1264], IV.13.2.3sc), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 20.2
1265 Summa Theologicae
p.20 Aquinas says a fertilized egg is not human, and has no immortal soul
     Full Idea: In Aquinas's view the fertilized egg is not, either at the moment of conception or for quite a while afterwards, endowed with an immortal soul. In fact, technically speaking, it is not even human.
     From: report of Thomas Aquinas (Summa Theologicae [1265]) by R Martin / J Barresi - Introduction to 'Personal Identity' p.20
     A reaction: It is pointed at that therefore Aquinas does not give good support for modern Catholic views on abortion. There is certainly no reason why a human zygote should be ensouled from the start, as God may do this whenever He wishes.
p.39 Aquinas saw angels as separated forms, rather than as made of 'spiritual matter'
     Full Idea: Unlike some of his contemporaries, Aquinas does not think that there is a 'spiritual matter' that angels or disembodied souls have as one of their components, but rather that they are separated forms that configure no matter at all.
     From: report of Thomas Aquinas (Summa Theologicae [1265]) by Kretzmann/Stump - Aquinas, Thomas 10
     A reaction: 'Separated forms' sounds like the modern concept of abstract entities, meaning that souls and angels exist in the way that platonists believe numbers exist. How else might Aquinas have understood them?
p.39 Sensations are transmitted to 'internal senses' in the brain, chiefly to 'phantasia' and 'imagination'
     Full Idea: Sensory species received in external senses are transmitted to 'internal senses', organs located in the brain. The most important of these for cognition are 'phantasia' and 'imagination' (part of phantasia), which produce and preserve 'phantasms'.
     From: report of Thomas Aquinas (Summa Theologicae [1265]) by Kretzmann/Stump - Aquinas, Thomas 11
     A reaction: This seems to make Aquinas a representative realist. I add this to my portfolio of philosophical faculties - those required by philosophy, rather than by psychology or neuroscience.
p.42 Aquinas attributes freedom to decisions and judgements, and not to the will alone
     Full Idea: Aquinas conceives of freedom as free decision or judgement, which cannot be attributed to the will alone.
     From: report of Thomas Aquinas (Summa Theologicae [1265]) by Kretzmann/Stump - Aquinas, Thomas 12
     A reaction: This idea might improve the free will debate considerably, because it is not clear what sort of thing a 'will' is, and it is not clear how an entity can be 'free' in isolation, by its intrinsic nature. Isn't all freedom contextual?
p.117 Aquinas wanted, not to escape desire, but to transform it for moral ends
     Full Idea: The Aristotelianism of Thomas Aquinas (unlike St Augustine's Platonism) is not concerned with escaping from the snares of the world and of desire, but with transforming desire for moral ends.
     From: report of Thomas Aquinas (Summa Theologicae [1265]) by Alasdair MacIntyre - A Short History of Ethics Ch.9
     A reaction: This is very close to Aristotle himself, for whom education of the feelings (into good habits, and then true virtues) was central. Education of feelings should be central to all education (though young psychopaths may show resistance).
p.198 Life aims at the Beatific Vision - of perfect happiness, and revealed truth
     Full Idea: Aquinas describes the ultimate end of human life as the Beatific Vision, a state that is simultaneously the enjoyment of perfect happiness and a perfect revelation of truth.
     From: report of Thomas Aquinas (Summa Theologicae [1265]) by Linda Trinkaus Zagzebski - Virtues of the Mind II 4.2
     A reaction: I like that a lot, even though my idea of the revelation of truth is very distant from that of Aquinas. Ignorant happiness is not much of an aspiration.
p.573 If you assume that there must be a necessary being, you can't say which being has this quality
     Full Idea: To those who assume the existence of a necessary being, and would only know which among all things had to be regarded as such a thing, one could not answer: This thing here is the necessary being
     From: comment on Thomas Aquinas (Summa Theologicae [1265]) by Immanuel Kant - Critique of Pure Reason A612/B640
     A reaction: See Aquinas in Idea 1431. Kant makes a nice point. You might turn out to be the necessary being? How could you tell? You only know that there must be one lurking somewhere. I could be a slug. Aquinas makes a huge leap to God.
1a 18.2c p.324 Bodies are three-dimensional substances
     Full Idea: Bodies are those substances in which one finds three dimensions.
     From: Thomas Aquinas (Summa Theologicae [1265], 1a 18.2c), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 16.2
     A reaction: Pasnau points out that this extensional view of physical bodies was a commonplace long before Descartes. Presumably there are also non-dimensional substances (such as angels?).
1a 76.4c p.575 Humans only have a single substantial form, which contains the others and acts for them
     Full Idea: A human being has no substantial form other than the intellective soul alone, and it contains the sensitive and nutritive souls, and all lower forms, and it alone brings about whatever it is that less perfect forms bring about in other things.
     From: Thomas Aquinas (Summa Theologicae [1265], 1a 76.4c), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 25.1
     A reaction: He says brutes and plants also have a single soul. Pasnau says this is Aquinas's most distinctive doctrine, because other thinkers postulate a whole hierarchy of substantial forms.
1a,q.14,art 1 p. A knowing being possesses a further reality, the 'presence' of the thing known
     Full Idea: Knowing beings are differentiated from non-knowing beings by this: non-knowing beings have only their own reality, but knowing beings are capable of possessing also the reality of something else, ...a presence of the thing known produced by this thing.
     From: Thomas Aquinas (Summa Theologicae [1265], 1a,q.14,art 1)
     A reaction: [Quoted by Ryan Meade in a talk at Pigotts] A famous and much discussed remark. Aquinas was a direct realist about perception, so this presence seems to be the thing itself, rather than a 'representation'.
1a.75.2c p.39 The human intellectual soul is an incorporeal, subsistent principle
     Full Idea: It is necessary to say that that which is the principle of intellective activity, what we call the soul of a human being, is an incorporeal, subsistent principle.
     From: Thomas Aquinas (Summa Theologicae [1265], 1a.75.2c), quoted by Kretzmann/Stump - Aquinas, Thomas 10
     A reaction: Note 'subsistent' rather than 'existent' (capable of independence?). This identifies the immortal soul with the conscious mind. 'Principle' is an odd word, presumably with roots in Aristotle. It seems to be an Aristotelian 'form' [morphe].
1a2ae Q.61 a.3 p.9 Temperance prevents our passions from acting against reason
     Full Idea: The passions may incite us to something against reason, and so we need a curb, which we name 'temperance'.
     From: Thomas Aquinas (Summa Theologicae [1265], 1a2ae Q.61 a.3), quoted by Philippa Foot - Virtues and Vices II
     A reaction: I am increasingly unclear what 'reason' means in contexts like these. It seems to mean no more than the awareness of greater goods than the indulgence of passion. Without that awareness, high intelligence couldn't produce temperance.
2.1.13.2 p.54 We must know the end, know that it is the end, and know how to attain it
     Full Idea: Perfect knowledge of the end consists in not only apprehending the thing which is the end but also knowing it under the aspect of the end and the relation of the means to that end.
     From: Thomas Aquinas (Summa Theologicae [1265], 2.1.13.2), quoted by Philippa Foot - Natural Goodness 4
     A reaction: We don't talk much now about 'perfect' knowledge of something, but I suppose this is the necessary and sufficient conditions. If you complete the checklist, your knowledge should be perfect (if the list is right).
Art 1, Obj 3 p.31 If the existence of truth is denied, the 'Truth does not exist' must be true!
     Full Idea: Whoever denies the existence of truth grants that truth does not exist: and if truth does not exist, then the proposition 'Truth does not exist' is true: and if there is anything true, there must be truth.
     From: Thomas Aquinas (Summa Theologicae [1265], Art 1, Obj 3)
     A reaction: A classic example of turning the tables, also applicable to anyone who firmly denies knowledge, or that words are meaningful, or says that meaning needs verification. However, one measily truth is not much consolation.
Art 1, Obj 3 p.32 Some things are self-evident to us; others are only self-evident in themselves
     Full Idea: A thing can be self-evident in either of two ways: on the one hand, self-evident in itself, though not to us; on the other hand, self-evident in itself, and to us.
     From: Thomas Aquinas (Summa Theologicae [1265], Art 1, Obj 3)
     A reaction: A clear distinction, which is hard to deny, though there are lots of borderline cases. Self-evident to genius, and self-evident to future genius. Self-evident to almost everyone. Goldbach's Conjecture may be self-evident but unknowable.
Art 1, Obj 3 p.32 A proposition is self-evident if the predicate is included in the essence of the subject
     Full Idea: A proposition is self-evident because the predicate is included in the essence of the subject. E.g. Man is an animal, because animal is included in the essence of man.
     From: Thomas Aquinas (Summa Theologicae [1265], Art 1, Obj 3)
     A reaction: Aquinas focuses on the essence of the subject, where Kant embraces the whole concept of the subject. Is it self-evident that we are genetically related to apes? Yes, to a geneticiist. Is that part of human essence? No. So Kant wins.
Art 1, Obj 3 p.32 We can't know God's essence, so his existence can't be self-evident for us
     Full Idea: Because we do not know the essence of God, the proposition 'God exists' is not self-evident to us, but needs to be demonstrated by things that are more known to us.
     From: Thomas Aquinas (Summa Theologicae [1265], Art 1, Obj 3)
     A reaction: Depends on his definition of self-evidence (Idea 21250), which needs knowledge of the essence of the subject. Anselm required 'understanding' of the concept. One might understand the existence criteria without knowing the whole essence. Anselm wins.
Ch.5 §85.1 p.133 Abstracting A from B generates truth, as long as the connection is not denied
     Full Idea: Abstacting A from B can mean denying A's connection with B, or simply thinking A without thinking B. Abstracting what in reality is connected generates falsehood if done the first way, but not if done the second.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.1)
     A reaction: Despite Geach's denials, this seems to make Aquinas a classic abstractionist. He goes on to distinguish two sorts of abstraction, but he certainly thinks of abstraction from sense experience as a revelation about the nature of reality.
Ch.5 §85.1 p.133 We understand the general nature of things by ignoring individual peculiarities
     Full Idea: If we think what defines a stone, man or horse, without thinking of any individual peculiarities it may have, this is precisely what we do when we abstract the general nature of what we understand from any particular way in which we imagine it.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.1)
     A reaction: This may not be simple abstraction from sense experience, since there would obviously be a threatened circularity in the process. Do you need to know the essential definition first, in order to discard the individual peculiarities?
Ch.5 §85.1 p.133 Mathematical objects abstract both from perceived matter, and from particular substance
     Full Idea: Objects of mathematics abstract from perceived matter both in particular and in general, though from thought matter (substance as underlying quality) only in particular and not in general.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.1)
     A reaction: This appears to be a thoroughly abstractionist view of the way in which humans create mathematics. Aquinas explicitly denies the Platonic view that the numbers already have abstract existence, awaiting our discovery.
Ch.5 §85.1 p.134 The mind must produce by its own power an image of the individual species
     Full Idea: The agent mind must itself turn to images, and produce by its own power in the receptive mind a representation as to species of whatever the images represent as individual.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.1)
     A reaction: Unlike much of this section, this sentence supports Geach's claim that Aquinas agrees with him - that the mind creates its concepts, rather than 'abstracting' them from experience.
Ch.5 §85.1 p.134 Very general ideas (being, oneness, potentiality) can be abstracted from thought matter in general
     Full Idea: There are even things we can abstract from thought matter in general, things like being and oneness and potentiality and realization.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.1)
     A reaction: The Aristotelian 'potentiality' means possibility, which means that modality is understood by abstraction. Aquinas seems to have four levels: particular perceived, general perceived, particular thought, and general thought. This is the highest level.
Ch.5 §85.1 p.134 The mind abstracts generalities from images, but also uses images for understanding
     Full Idea: Our mind both abstracts the species from images when it attends to the general nature of things, and understand the species in the images when it has recourse to the images in order to understand the things whose species it has abstracted.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.1)
     A reaction: Geach claims that the second half of this idea means that Aquinas is not an abstractionist, but he seems to be explictly abstractionist about the way in which we create higher level concepts from lower ones.
Ch.5 §85.2 p.135 Mental activity combines what we sense with imagination of what is not present
     Full Idea: Mental activity combines two activities which in the senses are distinct: exterior perception in which we are simply affected by what we sense, and interior imagination in which we create images of things that are not, and never have been present.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.2)
     A reaction: Geach cites this thought to show that he is anti-abstractionist, since mind creates images, and these can arise from things which have not been experienced. Any defence of abstractionism must allow an active power to imagination.
Ch.5 §85.2 p.136 Particular instances come first, and (pace Plato) generalisations are abstracted from them
     Full Idea: The generality attaching to a nature - its relatedness to many particular instances - results from abstraction, so in this sense a generalized nature presupposes its instances, and does not, as Plato thought, precede them.
     From: Thomas Aquinas (Summa Theologicae [1265], Ch.5 §85.2)
     A reaction: This seems to be a quite explicit endorsement of abstractionism by Aquinas, despite all Geach's assertions to the contrary.
I q11 ar2 ad4 p.36 Being implies distinctness, which implies division, unity, and multitude
     Full Idea: What first comes to mind is being; secondly, that this being is not that being, and thus we apprehend division as a consequence; thirdly, comes the notion of one; fourthly the notion of multitude.
     From: Thomas Aquinas (Summa Theologicae [1265], I q11 ar2 ad4), quoted by Roderick Chisholm - Person and Object 1.5
     A reaction: This is one of the best things I have read on 'being'. It is the Aristotelian recognition that we can only study being by studying identity, and that this leads on to wider metaphysics. Other approaches to being are dead ends.
Ia,Q2,Art3,Ob1 p.82 God does not exist, because He is infinite and good, and so no evil should be discoverable
     Full Idea: If one of two contraries be infinite, the other would be altogether destroyed. But the name God means that He is infinite goodness. If therefore God existed there would be no evil discoverable; but there is evil in the world. Therefore God does not exist.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Ob1)
     A reaction: This is not, of course, the opinion of Aquinas. I love the way he states the opposition's arguments so lucidly. The modern problem usually talks of God's omnipotence, rather than infinity. His formulation allows that there might be undiscoverable evil.
Ia,Q2,Art3,Ob1rep p.85 It is part of God's supreme goodness that He brings good even out of evil
     Full Idea: As Augustine says, God would not allow any evil to exist in his works, unless he were to bring good even out of evil. It is part of the infinite goodness of God, that He allows evil to exist and out of it produces good.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Ob1rep)
     A reaction: Are God's powers so limited that He could not have achieved an equal amount of good without having to indulge in some evil first?
Ia,Q2,Art3,Ob2 p.82 Non-human things are explicable naturally, and voluntary things by the will, so God is not needed
     Full Idea: All natural things can be reduced to one principle, which is nature; and all voluntary things can be reduced to one principle, which is human reason, or will. Therefore God does not exist.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Ob2)
     A reaction: Not, of course, the opinion of Aquinas. So the possibility of naturalism (assuming the human will can be further reduced to nature) was a clear option in the thirteenth century. In reply Aquinas cites his Fifth Way.
Ia,Q2,Art3,Ob2 p.82 Supposing many principles is superfluous if a few will do it
     Full Idea: It is superfluous to suppose that what can be accounted for by a few principles has been produced by many.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Ob2)
     A reaction: Notice that this is 'superfluous' rather than 'wrong'. But ten people can lift a piano which could have been lifted by eight. Note that this is 150 years before Ockham.
Ia,Q2,Art3,Reply p.83 Way 1: the infinite chain of potential-to-actual movement has to have a first mover
     Full Idea: A thing can only be reduced from potentiality to actuality by something actual. A thing can never be in actuality and potentiality in the same respect. So what is moved must be moved by another. But this cannot go on to infinity, with no first mover.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Reply)
     A reaction: [compressed] This relies on the Aristotelian ideas of potentiality and actuality. We might talk about things moving, but lacking the 'power' to move. This is almost identical to Plato in 'The Laws' (which I guess Aquinas knew nothing of).
Ia,Q2,Art3,Reply p.84 Way 2: no effect without a cause, and this cannot go back to infinity, so there is First Cause
     Full Idea: If there is no first cause among efficient causes, there is no ultimate or intermediate cause. That in efficient causes it is possible to go on to infinity is plainly false. So it is necessary to admit a first efficient cause, which everyone calls God.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Reply)
     A reaction: [compressed] It doesn't seem to follow at all that the First Cause is God. There could be a single thing like the Phoenix, with unique self-causing properties. Or a quantum fluctuation.
Ia,Q2,Art3,Reply p.84 Way 3: contingent beings eventually vanish, so continuity needs a necessary being
     Full Idea: That which can not-be at some time is not. So if everything can not-be, then once there was nothing in existence. If so, it would have been impossible for anything to have begun to exist. So there must be some being having of itself its own necessity.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Reply)
     A reaction: [compressed] Why can't things take it in turns to not-be, so that something is always on duty? Maybe it is a feature of things that they bring other things into existence (e.g. virtual particles)?
Ia,Q2,Art3,Reply p.85 Way 4: the source of all qualities is their maximum, so something (God) causes all perfections
     Full Idea: More and less are predicated of different things according as they resemble in their different ways something which is the maximum. The maximum of a genus is the cause of all in that genus. So there must be something causing the perfections of all beings.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Reply)
     A reaction: [compressed] The argument makes a startling jump from each quality (like heat or nobility) having a maximum, to their being a single entity (a 'being' at that) which is the sole source of all human perfections.
Ia,Q2,Art3,Reply p.85 Way 5: mindless things act towards an obvious end, so there is an intelligent director
     Full Idea: Things which lack knowledge, such as natural bodies, act for an end, which is usually in the same way, to obtain the best result. Hence they achieve their end designedly. Hence some intelligent being exists by whom all natural things are directed.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia,Q2,Art3,Reply)
     A reaction: [compressed] This is Greek teleology with a vengeance. Plants probably illustrate best what he has in mind. There is obvious teleology in human affairs, and there is a sort of teleology in living things, but we take the end to be reinforced by success.
Ia.85.5c p.40 First grasp what it is, then its essential features; judgement is their compounding and division
     Full Idea: The intellect first apprehends the quiddity of a thing. ...Then it acquires the properties, accidents and dispositions associated with the thing's essence. It must proceed from one compounding or dividing of aspects to another, which is reasoning.
     From: Thomas Aquinas (Summa Theologicae [1265], Ia.85.5c), quoted by Kretzmann/Stump - Aquinas, Thomas 11
     A reaction: [compressed] Tracking the process of acquiring knowledge of a thing (rather than necessary and sufficient conditions for full knowledge) is closer to Quine's naturalised epistemology than to the standard analytic approach to the concept of knowledge.
IaIIae.18.5c p.43 For humans good is accordance with reason, and bad is contrary to reason.
     Full Idea: A human being's good is existing in accordance with reason, while what is bad for a human being is whatever is contrary to reason.
     From: Thomas Aquinas (Summa Theologicae [1265], IaIIae.18.5c), quoted by Kretzmann/Stump - Aquinas, Thomas 13
     A reaction: For anyone who thought Kant invented the idea that morality derives from reason. This idea of Aquinas is a fairly precise echo of the stoic view (which influenced Kant). Is there a circularity? Is it irrational because bad, or bad because irrational?
IaIIae.92.1, ad 4 p.44 Tyrannical laws are irrational, and so not really laws
     Full Idea: A tyrannical law, since it is not in accord with reason, is not unconditionally a law, but is rather a perversion of law.
     From: Thomas Aquinas (Summa Theologicae [1265], IaIIae.92.1, ad 4), quoted by Kretzmann/Stump - Aquinas, Thomas 13
     A reaction: Only a belief in natural law can give a basis for such a claim. Positivists will say a tyrannical law is unconditionally a law like any other, but a bad one.
IaIIae.94.2c p.44 Right and wrong actions pertain to natural law, as perceived by practical reason
     Full Idea: All things to be done or to be avoided pertain to the precepts of natural law, which practical reasoning apprehends naturally as being human goods.
     From: Thomas Aquinas (Summa Theologicae [1265], IaIIae.94.2c), quoted by Kretzmann/Stump - Aquinas, Thomas 13
     A reaction: No mention of God, but you feel the divine presence in the background. He also cites 'eternal law'. No coincidence that the atheist Hobbes rejected natural law. Personally I would offer an atheistic defence of natural law, based on human nature.
I-II q56 a5 obj3 p.277 Sensation prepares the way for intellectual knowledge, which needs the virtues of reason
     Full Idea: Knowledge of truth is not consummated in the sensitive powers of apprehension, for these prepare the way to intellectual knowledge. And therefore in these powers there are none of the virtues by which we know truth; these are in the intellect or reason.
     From: Thomas Aquinas (Summa Theologicae [1265], I-II q56 a5 obj3), quoted by Linda Trinkaus Zagzebski - Virtues of the Mind III 2.2
     A reaction: A gem of a quotation for Zagzebski's thesis, that knowledge is defined in terms of the intellectual virtues. The only virtues of perception are in focusing and paying attention to features. Good eyesight is a biological 'virtue', I suppose.
III Supp 94/1 p.49 Those in bliss have their happiness increased by seeing the damned punished
     Full Idea: In order that the bliss of the saints may be more delightful for them, and they may render more copious thanks to God for it, it is given to them to see perfectly the punishment of the damned.
     From: Thomas Aquinas (Summa Theologicae [1265], III Supp 94/1), quoted by Friedrich Nietzsche - On the Genealogy of Morals I.§15
     A reaction: This has probably been repudiated by the Church of England. Justice should be seen to be done. Presumably you mustn't gloat, or you join them.
Pt II p.211 For Aquinas a war must be in a just cause, have proper authority, and aim at good
     Full Idea: Aquinas argued that on three conditions war can be justified: first, that there is a just cause; second, that it is begun on proper authority; and third, that it is waged with right intention, for 'the advancement of good, or the avoidance of evil'.
     From: report of Thomas Aquinas (Summa Theologicae [1265], Pt II) by A.C. Grayling - Among the Dead Cities Ch.6
     A reaction: But see also Idea 7292. Nowadays we are rightly suspicious of all three conditions. Evil people seem to think their cause is just; authority has often been seized by violence, or is being abused; and people seem confused about what is good or evil.
Q. 110 p.239 Types of lying: Speak lies, intend lies, intend deception, aim at deceptive goal?
     Full Idea: Lying can involve (1) speaking false words, (2) the intention to speak false words, (3) the intention of bringing about deception, and (4) the ultimate goal of one's deception.
     From: report of Thomas Aquinas (Summa Theologicae [1265], Q. 110) by Tuckness,A/Wolf,C - This is Political Philosophy 10 'Lying'
     A reaction: It's a start, but much more is needed to clarify lying. Irony is an obvious problem with (1).
Q85 1 Ad 1 p.159 We can just think of an apple's colour, because the apple is not part of the colour's nature
     Full Idea: The apple is not part of the nature of the colour, and so nothing prevents one from understanding the colour while understanding nothing of the apple.
     From: Thomas Aquinas (Summa Theologicae [1265], Q85 1 Ad 1)
     A reaction: This helps to clarify why the procedure of 'ignoring' features is possible. It suggests that some features might be too entangled with the substance (too essential?) to be thus ignored. I can't think of an example, though. Why not?!
Q85 1 Ad 1 p.159 Abstracting either treats something as separate, or thinks of it separately
     Full Idea: Abstracting takes place in two ways: by composition and division, understanding something to be not in another or to be separated from it; and by a simple and unconditioned consideration, understanding one thing while not considering the other at all.
     From: Thomas Aquinas (Summa Theologicae [1265], Q85 1 Ad 1)
     A reaction: The second way is by 'ignoring', which he says cannot contain error. The first seems to be considering some mode of a thing to be actually separate from the thing, which could clearly be erroneous. Ignoring makes to commitment to a unity.
Q85 1 Reply p.158 We abstract forms from appearances, and acquire knowledge of immaterial things
     Full Idea: To cognize that which is in individual matter, not as it is in such matter, is to abstract the form from the individual matter that the phantasms represents. Thus we come to a degree of cognition of immaterial things.
     From: Thomas Aquinas (Summa Theologicae [1265], Q85 1 Reply)
     A reaction: This offers abstraction as a kind of inference to best explanation which takes us beyond immediate empirical experience to what is behind it. Aquinas thinks the concepts and explanation are spiritual, but they may be generalities and essences.
Q85 Ad2 p.160 Numbers and shapes are abstracted by ignoring their sensible qualities
     Full Idea: Quantities such as numbers and dimensions, and also shapes (which are the limits of quantities) can be considered without their sensible qualities, which is for them to be abstracted from sensible matter.
     From: Thomas Aquinas (Summa Theologicae [1265], Q85 Ad2)
     A reaction: His account relies on underlying substance, which is where quantity is to be found (presumably because a substance is the epitome of a unit).
Q85 Ad2 p.160 Mathematics can be abstracted from sensible matter, and from individual intelligible matter
     Full Idea: Intellect can abstract mathematical species from sensible matter, both individual and common. Yet it cannot abstract such species from common intelligible matter, but only from individual intelligible matter.
     From: Thomas Aquinas (Summa Theologicae [1265], Q85 Ad2)
     A reaction: The idea is that common intelligible matter lacks underlying substance, which is where quantity is to be found.
Q85 Ad4 p.161 Species are abstracted from appearances by ignoring individual conditions
     Full Idea: The agent intellect abstracts intelligible species from phantasms insofar as through the power of the agent intellect we can take into our consideration the natures of the species without the individual conditions.
     From: Thomas Aquinas (Summa Theologicae [1265], Q85 Ad4)
     A reaction: There might be a threatened circularity here, in trying to decide which features to ignore and which to retain. If we saw a hundred horses with a white nose blaze, we still wouldn't be sure that this was essential to a horse. Innate notions of species??
Q85 Art2 p.162 Understanding consists entirely of grasping abstracted species
     Full Idea: Of the thing understood all that is within the actually understanding intellect is the abstracted intelligible species.
     From: Thomas Aquinas (Summa Theologicae [1265], Q85 Art2)
     A reaction: Abstraction is never supposed to be a luxury bolt-on, but is always seen (in this tradition, and presumably in the modern one), as essential to the intellect, and its way of coming to understand the world. Aristotelian definition is behind this idea.
1266 On Aristotle's 'Metaphysics'
V.9.890 p.230 Different genera are delimited by modes of predication, which rest on modes of being
     Full Idea: Being is delimited into different genera in accord with different modes of predicating, which depend on different modes of being.
     From: Thomas Aquinas (On Aristotle's 'Metaphysics' [1266], V.9.890), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 12.3
     A reaction: I like this. When people say that predication is the way we divide things up, and go all linguistic-relativist about things, they forget how closely language not only describes reality, but arises out of, or is even caused by, reality. 'Grue' is silly.
1267 De Ente et Essentia (Being and Essence)
p.196 The principle of diversity for corporeal substances is their matter
     Full Idea: In the view of Aquinas, while substantial form is the ultimate ground of identity and difference of angels, it is matter that provides a principle of diversity in the case of corporeal substances.
     From: report of Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 5.2.3
     A reaction: This is at least as good a proposal as their apatial location. There is more chance of reidentifying matter than of precisely reidentifying a spatial location. Two indistinguishable spheres remain the classic problem case (of Max Black, Idea 10195)
23 p.17 If definitions must be general, and general terms can't individuate, then Socrates can't be defined
     Full Idea: Socrates has no definition if definitions by their nature must be in purely general terms, and if no purely general terms can succeed in uniquely singling out this signated matter.
     From: report of Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], 23) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 1.1.2
     A reaction: There seem to be two models. That general terms actually individuate the matter of Socrates, or that they cross-reference to (so to speak) define Socrates 'by elimination', as the only individual that fits. But the latter is a poor definition.
p.100 p.100 If the form of 'human' contains 'many', Socrates isn't human; if it contains 'one', Socrates is Plato
     Full Idea: If (in the Platonic view) manyness was contained in humanness it could never be one as it is in Socrates, and if oneness was part of its definition then Socrates would be Plato and the nature couldn't be realised more than once.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.100)
     A reaction: I suppose the reply is that since we are trying to explain one-over-many, then this unusual combination of both manyness and oneness is precisely what distinguishes forms from other ideas.
p.102 p.102 The mind constructs complete attributions, based on the unified elements of the real world
     Full Idea: Attribution is something mind brings to completion by constructing propositional connections and disconnections, basing itself on real-world unity possessed by the things being attributed to one another.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.102)
     A reaction: This compromise story seems to me to be exactly right. I take it that we respond to the real joints of nature, but using thought and language which is riddled with convention.
p.103 p.103 A simple substance is its own essence
     Full Idea: A simple substance is its own essence.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.103)
     A reaction: Aquinas takes complex substances to have their essences in various ways, but this thought is the basis of all essence. Presumably the Greek word 'ousia' names the key ingredient.
p.103 p.103 A cause can exist without its effect, but the effect cannot exist without its cause
     Full Idea: When things are so related that one causes the other to exist, the cause can exist without what it causes but not vice versa.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.103)
     A reaction: This is open to question, if causes are supposed to be sufficient for effects. Presumably Aquinas would support the view that if the cause had not been, the effect would not have happened. But the current idea indicates the priority relation.
p.92 p.92 Essence is something in common between the natures which sort things into categories
     Full Idea: Since being as belonging to a category expresses the 'isness' of things, and belongs to all ten Aristotelian categories, essence must be something all the natures that sort different beings into genera and species have in common.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92)
     A reaction: I like this because it is the essence which does the sorting, not the sorting which defines the essence (which seems to me to be a deep and widespread confusion).
p.92 p.92 If affirmative propositions express being, we affirm about what is absent
     Full Idea: If being is what makes propositions true, then anything we can express in an affirmative proposition, however unreal, is said to be; so lacks and absences are, since we say that absences are opposed to presences, and blindness exists in an eye.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92)
     A reaction: See Idea 11194 for the alternative Aristotelian approach to being, according to categories. Do absences and lacks have real essences, or causal properties? The absence of the sentry may cause the loss of the city.
p.92 p.92 The definitions expressing identity are used to sort things
     Full Idea: What sorts things into their proper genus and species are the definitions that express what they are.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92)
     A reaction: This is straight from Aristotle, though Aristotle's view is a little more complex, I think. If the definitions 'express what they are', then definitions seem to specify the essence.
p.92 p.92 Definition of essence makes things understandable
     Full Idea: It is definition of essence that makes things understandable.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.92)
     A reaction: The aim of philosophy is understanding, which is achieved by successful explanation. I totally agree with this Aristotelian view, so neatly summarised by Aquinas.
p.93 p.93 Properties have an incomplete essence, with definitions referring to their subject
     Full Idea: Incidental properties have an incomplete essence, and need to refer in their definitions to their subject, lying outside their own genus.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.93)
     A reaction: These are 'incidental' properties, but it is a nice question whether properties have essences. Presumably they must have if they are universals, or platonic Forms. The notion of being 'strong' can be defined without specific examples.
p.93 p.93 The definition of a physical object must include the material as well as the form
     Full Idea: Form alone cannot be a composite substance's essence. For a thing's essence is expressed by its definition, and unless the definition of a physical substance included both form and material, the definition wouldn't differ from mathematical objects.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.93)
     A reaction: This is the sort of thoroughly sensible remark that you only get from the greatest philosophers. Minor philosophers fall in love with things like forms, and then try to use them to explain everything.
p.94 p.94 It is by having essence that things exist
     Full Idea: It is by having essence that things exist.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.94)
     A reaction: Compare Idea 11199, which gives a fuller picture. This idea seems to suggest essence as the cause of existence, which sounds wrong. Perhaps essence is a necessary condition of existence, but it is necessary that nothing indeterminate can exist?
p.95 p.95 Specific individual essence is defined by material, and generic essence is defined by form
     Full Idea: Specific essence differs from generic essence by being demarcated: individuals are demarcated within species by dimensionally defined material, but species within genus by a defining differentiation taken from the form.
     From: Thomas Aquinas (De Ente et Essentia (Being and Essence) [1267], p.95)
     A reaction: It clearly won't be enough to define an individual just to define its material and its shape. The material might also be essential to the genus, as when defining fire. Probably not very helpful.
1267 Disputed questions about truth
I.1c p.37 Being is basic to thought, and all other concepts are additions to being
     Full Idea: Being is inherently intellect's most intelligible object, in which it finds the basis of all conceptions. ...All of intellect's other conceptions must be arrived at by adding to being, insofar as they express what is not expressed by 'being' itself.
     From: Thomas Aquinas (Disputed questions about truth [1267], I.1c), quoted by Kretzmann/Stump - Aquinas, Thomas 09
     A reaction: I like the word 'intelligible' here. We might know reality, or be aware of appearances, but what is intelligible lies nicely in between. What would Berkeley make of that? I presume 'intelligible' means 'makes good sense'.
I.1c p.37 Truth is the conformity of being to intellect
     Full Idea: The word 'true' expresses the conformity of a being to intellect.
     From: Thomas Aquinas (Disputed questions about truth [1267], I.1c), quoted by Kretzmann/Stump - Aquinas, Thomas 09
     A reaction: I believe in a 'robust' theory of truth, but accept that the concept of 'correspondence' has major problems. So I embrace with delight the word 'conformity'. I offer the world The Conformity Theory of Truth! 'Conform' is suitably vague.
1267 Quodlibeta
8.2.1 p.8 Minds take in a likeness of things, which activates an awaiting potential
     Full Idea: What the mind takes in is not some material element of the agent, but a likeness of the agent actualising some potential the patient already has. This, for example, is the way our seeing takes in the colour of a coloured body.
     From: Thomas Aquinas (Quodlibeta [1267], 8.2.1)
     A reaction: This is exactly right. Descartes agreed. It works for colour, but not (obviously) for cheese graters.
8.2.2 p.19 Initial universal truths are present within us as potential, to be drawn out by reason
     Full Idea: For present in us by nature are certain initial truths everyone knows, in which lie potentially known conclusions our reasons can draw out and make actually known.
     From: Thomas Aquinas (Quodlibeta [1267], 8.2.2)
     A reaction: Note that these are truths rather than concepts, but that they have to be 'drawn out' by reason. This is Descartes' view of the matter, where the 'natural light' of reason is needed to articulate what is innate, such as geometry.
8.2.2 p.20 Senses grasp external properties, but the understanding grasps the essential natures of things
     Full Idea: Our imagination and senses grasp only the outer properties of things, not their natures. ...Understanding, however, grasps the very substance and nature of things, so that what is represented in understanding is a likeness of thing's very essence.
     From: Thomas Aquinas (Quodlibeta [1267], 8.2.2)
     A reaction: This is exactly the picture I endorse for modern science. Explanation is the path to understanding, and that must venture beyond immediate experience.
IX.2.2 p.184 Whiteness does not exist, but by it something can exist-as-white
     Full Idea: Whiteness is said to exist not because it subsists in itself, but because by it something has existence-as-white.
     From: Thomas Aquinas (Quodlibeta [1267], IX.2.2), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 10.2
     A reaction: It seems unavoidable to refer to the whiteness as 'it'. It might be called the 'adverbial' theory of properties, as ways of doing something.
1268 Summa Contra Gentiles
I.1.6 p.45 Wise people should contemplate and discuss the truth, and fight against falsehood
     Full Idea: The role of the wise person is to meditate on the truth, especially the truth regarding the first principle, and to discuss it with others, but also to fight against the falsity that is its contrary.
     From: Thomas Aquinas (Summa Contra Gentiles [1268], I.1.6), quoted by Kretzmann/Stump - Aquinas, Thomas 14
     A reaction: So nice to hear someone (from no matter how long ago) saying that wisdom is concerned with truth. If you lose your grip on truth (which many thinkers seem to have done) you must also abandon wisdom. Then fools rule.
I.66 p.27 Eternity coexists with passing time, as the centre of a circle coexists with its circumference
     Full Idea: The centre of a circle is directly opposite any designated point on the circumference. In this way, whatever is in any part of time coexists with what is eternal as being present to it even though past or future with respect to another part of time.
     From: Thomas Aquinas (Summa Contra Gentiles [1268], I.66), quoted by Robin Le Poidevin - Past, Present and Future of Debate about Tense 2 c
     A reaction: A nice example of a really cool analogy which almost gets you to accept something which is actually completely incomprehensible.
III.67 p.42 Without God's influence every operation would stop, so God causes everything
     Full Idea: If God's divine influence stopped, every operation would stop. Every operation, therefore, of everything is traced back to him as cause.
     From: Thomas Aquinas (Summa Contra Gentiles [1268], III.67), quoted by Brian Davies - Introduction to the Philosophy of Religion 3 'Freedom'
     A reaction: If the systematic interraction of mind and body counts as an 'operation', then this seems to imply Occasionalism.
1268 Sententia on 'De Caelo'
I.22.228 p.35 Philosophy aims to know the truth about the way things are
     Full Idea: The study of philosophy has as its purpose to know not what people have thought, but rather the truth about the way things are.
     From: Thomas Aquinas (Sententia on 'De Caelo' [1268], I.22.228), quoted by Kretzmann/Stump - Aquinas, Thomas 05
     A reaction: I agree with this deeply unfashionable opinion. Of course, modern investigations must be more sensitive to biases built into language, culture and conceptual schemes. But I am one of those sad old folks who still think truths can be stated.
1268 On the spiritual perfection of life
26 p.35 Arguing with opponents uncovers truths, and restrains falsehoods
     Full Idea: There is no better way of uncovering the truth and keeping falsity in check than by arguing with people who disagree with you.
     From: Thomas Aquinas (On the spiritual perfection of life [1268], 26), quoted by Kretzmann/Stump - Aquinas, Thomas 05
     A reaction: Not the sort of attitude you associate with medieval scholastics, who are presumed to be dogmatists. How many modern philosophers actually have the courage to follow this advice?
1269 Sententia on 'Posterior Analytics'
1.2.9, 1.5.7 p.41 The fullest knowledge places a conclusion within an accurate theory
     Full Idea: Having 'scientia' is the fullest possible human cognition, by which one situates the fact expressed by a conclusion in an explanatory theory that accurately maps metaphysical or physical reality.
     From: report of Thomas Aquinas (Sententia on 'Posterior Analytics' [1269], 1.2.9, 1.5.7) by Kretzmann/Stump - Aquinas, Thomas 11
     A reaction: That is a perfect statement of my concept of knowledge. Explanatory theories must specify the essential natures of the entities involved. We don't aim for 'knowledge', we aim for the 'fullest possible cognition'. This account extend's Aristotle's.
1269 Quaestiones de Potentia Dei
q3 a16 ad 3-um p. 'One' can mean undivided and not a multitude, or it can add measurement, giving number
     Full Idea: There are two sorts of one. There is the one which is convertible with being, which adds nothing to being except being undivided; and this deprives of multitude. Then there is the principle of number, which to the notion of being adds measurement.
     From: Thomas Aquinas (Quaestiones de Potentia Dei [1269], q3 a16 ad 3-um)
     A reaction: [From a lecture handout] I'm not sure I understand this. We might say, I suppose, that insofar as water is water, it is all one, but you can't count it. Perhaps being 'unified' and being a 'unity' are different?
1269 Quaestiones de anima
11c p.578 One thing needs a single thing to unite it; if there were two forms, something must unite them
     Full Idea: One thing simpliciter is produced out of many actually existing things only if there is something uniting and tying them to each other. If Socrates were animal and rational by different forms, then to be united they would need something to make them one.
     From: Thomas Aquinas (Quaestiones de anima [1269], 11c), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 25.2
     A reaction: This is the reply to the idea that a single thing is just an interesting of many sortal essences. It presumes, of course, that a thing like a horse has something called 'unity'.
1271 Quaestiones Disputatae de Malo
Q6.06 p.172 The will can only want what it thinks is good
     Full Idea: Will's object is what is good, and so it cannot will anything but what is good.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.06)
Q6.07 p.173 The will must aim at happiness, but can choose the means
     Full Idea: The will is compelled by its ultimate goal (to achieve happiness), but not by the means to achieve it.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.07)
Q6.10 p.173 We are coerced into assent to a truth by reason's violence
     Full Idea: We are coerced into assent to a truth by reason's violence.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.10)
Q6.h to 05 p.181 Nothing can be willed except what is good, but good is very varied, and so choices are unpredictable
     Full Idea: Nothing can be willed except good, but many and various things are good, and you can't conclude from this that wills are compelled to choose this or that one.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 05)
Q6.h to 07 p.181 We don't have to will even perfect good, because we can choose not to think of it
     Full Idea: The will can avoid actually willing something by avoiding thinking of it, since mental activity is subject to will. In this respect we aren't compelled to will even total happiness, which is the only perfect good.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 07)
Q6.h to 12 p.182 The mind is compelled by necessary truths, but not by contingent truths
     Full Idea: Mind is compelled by necessary truths that can't be regarded as false, but not by contingent ones that might be false.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 12)
Q6.h to 15 p.182 Even a sufficient cause doesn't compel its effect, because interference could interrupt the process
     Full Idea: Even a sufficient cause doesn't always compel its effect, since it can sometimes be interfered with so that its effect doesn't happen
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 15)
Q6.h to 18 p.182 Knowledge may be based on senses, but we needn't sense all our knowledge
     Full Idea: All our knowledge comes through our senses, but that doesn't mean that everything we know is sensed.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 18)
Q6.h to 21 p.183 The will is not compelled to move, even if pleasant things are set before it
     Full Idea: The will is not compelled to move, for it doesn't have to want the pleasant things set before it.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 21)
Q6.h to 24 p.183 However habituated you are, given time to ponder you can go against a habit
     Full Idea: However habituated you are, given time to ponder you can go against a habit.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 24)
Q6.reply p.176 Without free will not only is ethical action meaningless, but also planning, commanding, praising and blaming
     Full Idea: If we are not free to will in any way, but are compelled, everything that makes up ethics vanishes: pondering action, exhorting, commanding, punishing, praising, condemning.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.reply)
     A reaction: If doesn't require some magical 'free will' to avoid compulsions. All that is needed is freedom to enact your own willing, rather than someone else's.
Q6.reply p.177 Good applies to goals, just as truth applies to ideas in the mind
     Full Idea: Good applies to all goals, just as truth applies to all forms mind takes in.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.reply)
     A reaction: In danger of being tautological, if good is understood as no more than the goal of actions. It seems perfectly possibly to pursue a wicked end, and perhaps feel guilty about it.
Q6.reply p.177 For the mind Good is one truth among many, and Truth is one good among many
     Full Idea: Good itself as taken in by mind is one truth among others, and truth itself as goal of mind's activity is one good among others.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.reply)
Q6.reply p.178 Because the will moves by examining alternatives, it doesn't compel itself to will
     Full Idea: Because will moves itself by deliberation - a kind of investigation which doesn't prove some one way correct but examines the alternatives - will doesn't compel itself to will.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.reply)
Q6.reply p.178 We must admit that when the will is not willing something, the first movement to will must come from outside the will
     Full Idea: We are forced to admit that, in any will that is not always willing, the very first movement to will must come from outside, stimulating the will to start willing.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.reply)
     A reaction: cf Nietzsche
Q6.reply p.179 If we saw something as totally and utterly good, we would be compelled to will it
     Full Idea: Something apprehended to be good and appropriate in any and every circumstance that could be thought of would compel us to will it.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.reply)
Q6.x2 p.175 Since will is a reasoning power, it can entertain opposites, so it is not compelled to embrace one of them
     Full Idea: Reasoning powers can entertain opposite objects. Now will is a reasoning power, so will can entertain opposites and is not compelled to embrace one of them.
     From: Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.x2)
1272 Super Epistolam Pauli Apostoli
p.192 If the soul achieves well-being in another life, it doesn't follow that I do
     Full Idea: Even if soul achieves well-being in another life, that doesn't mean I do or any other human being does.
     From: Thomas Aquinas (Super Epistolam Pauli Apostoli [1272])