Ideas of Thomas Aquinas, by Theme
[Italian, 1225 - 1274, Born Roccasecca, Italy. Dominican monk. Taught by Albertus Magnus. Based Paris, then Italy. Died at Fossanova. 'Doctor Angelicus'.]
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1. Philosophy / A. Wisdom / 2. Wise People
22115
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Wise people should contemplate and discuss the truth, and fight against falsehood
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1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
22101
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Philosophy aims to know the truth about the way things are
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2. Reason / A. Nature of Reason / 1. On Reason
1848
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We are coerced into assent to a truth by reason's violence
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2. Reason / A. Nature of Reason / 4. Aims of Reason
1858
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The mind is compelled by necessary truths, but not by contingent truths
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2. Reason / B. Laws of Thought / 6. Ockham's Razor
21267
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Supposing many principles is superfluous if a few will do it
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2. Reason / C. Styles of Reason / 1. Dialectic
22102
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Arguing with opponents uncovers truths, and restrains falsehoods
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2. Reason / D. Definition / 5. Genus and Differentia
13070
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If definitions must be general, and general terms can't individuate, then Socrates can't be defined [Cover/O'Leary-Hawthorne]
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11197
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The definitions expressing identity are used to sort things
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3. Truth / A. Truth Problems / 1. Truth
23176
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Truth is universal, but knowledge of it is not
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20621
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Types of lying: Speak lies, intend lies, intend deception, aim at deceptive goal? [Tuckness/Wolf]
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3. Truth / A. Truth Problems / 3. Value of Truth
1852
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For the mind Good is one truth among many, and Truth is one good among many
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3. Truth / A. Truth Problems / 9. Rejecting Truth
21248
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If the existence of truth is denied, the 'Truth does not exist' must be true!
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3. Truth / C. Correspondence Truth / 1. Correspondence Truth
22104
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Truth is the conformity of being to intellect
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5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
23173
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If a syllogism admits one absurdity, others must follow
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7. Existence / A. Nature of Existence / 3. Being / e. Being and nothing
11195
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If affirmative propositions express being, we affirm about what is absent
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7. Existence / A. Nature of Existence / 3. Being / f. Primary being
22103
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Being is basic to thought, and all other concepts are additions to being
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7. Existence / A. Nature of Existence / 3. Being / g. Particular being
15812
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Being implies distinctness, which implies division, unity, and multitude
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7. Existence / D. Theories of Reality / 5. Naturalism
21268
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Non-human things are explicable naturally, and voluntary things by the will, so God is not needed
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7. Existence / E. Categories / 4. Category Realism
16655
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Different genera are delimited by modes of predication, which rest on modes of being
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8. Modes of Existence / B. Properties / 8. Properties as Modes
16641
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Whiteness does not exist, but by it something can exist-as-white
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11201
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Properties have an incomplete essence, with definitions referring to their subject
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8. Modes of Existence / D. Universals / 6. Platonic Forms / d. Forms critiques
11205
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If the form of 'human' contains 'many', Socrates isn't human; if it contains 'one', Socrates is Plato
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9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
13090
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The principle of diversity for corporeal substances is their matter [Cover/O'Leary-Hawthorne]
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9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
17555
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'One' can mean undivided and not a multitude, or it can add measurement, giving number
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9. Objects / C. Structure of Objects / 2. Hylomorphism / d. Form as unifier
16765
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Humans only have a single substantial form, which contains the others and acts for them
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16766
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One thing needs a single thing to unite it; if there were two forms, something must unite them
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9. Objects / D. Essence of Objects / 1. Essences of Objects
11202
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It is by having essence that things exist
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9. Objects / D. Essence of Objects / 2. Types of Essence
11203
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Specific individual essence is defined by material, and generic essence is defined by form
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9. Objects / D. Essence of Objects / 4. Essence as Definition
11200
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The definition of a physical object must include the material as well as the form
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9. Objects / D. Essence of Objects / 5. Essence as Kind
11196
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Essence is something in common between the natures which sort things into categories
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9. Objects / D. Essence of Objects / 6. Essence as Unifier
11208
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A simple substance is its own essence
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11. Knowledge Aims / A. Knowledge / 2. Understanding
22170
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Senses grasp external properties, but the understanding grasps the essential natures of things
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11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
23175
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The conclusions of speculative reason about necessities are certain
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11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / b. Direct realism
21337
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A knowing being possesses a further reality, the 'presence' of the thing known
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12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
21249
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Some things are self-evident to us; others are only self-evident in themselves
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12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / a. Innate knowledge
22169
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Initial universal truths are present within us as potential, to be drawn out by reason
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12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
21250
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A proposition is self-evident if the predicate is included in the essence of the subject
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12. Knowledge Sources / B. Perception / 3. Representation
22168
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Minds take in a likeness of things, which activates an awaiting potential
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12. Knowledge Sources / C. Rationalism / 1. Rationalism
20224
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Sensation prepares the way for intellectual knowledge, which needs the virtues of reason
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12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
1860
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Knowledge may be based on senses, but we needn't sense all our knowledge
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13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
22109
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The fullest knowledge places a conclusion within an accurate theory [Kretzmann/Stump]
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14. Science / D. Explanation / 2. Types of Explanation / k. Explanations by essence
11198
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Definition of essence makes things understandable
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15. Nature of Minds / C. Capacities of Minds / 1. Faculties
22107
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Sensations are transmitted to 'internal senses' in the brain, chiefly to 'phantasia' and 'imagination' [Kretzmann/Stump]
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15. Nature of Minds / C. Capacities of Minds / 2. Imagination
9098
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Mental activity combines what we sense with imagination of what is not present
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15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
9092
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Abstracting A from B generates truth, as long as the connection is not denied
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15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
9093
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We understand the general nature of things by ignoring individual peculiarities
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9097
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The mind abstracts generalities from images, but also uses images for understanding
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9095
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Very general ideas (being, oneness, potentiality) can be abstracted from thought matter in general
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9099
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Particular instances come first, and (pace Plato) generalisations are abstracted from them
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10508
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Species are abstracted from appearances by ignoring individual conditions
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16. Persons / F. Free Will / 1. Nature of Free Will
22111
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Aquinas attributes freedom to decisions and judgements, and not to the will alone [Kretzmann/Stump]
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16. Persons / F. Free Will / 3. Constraints on the will
1855
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If we saw something as totally and utterly good, we would be compelled to will it
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16. Persons / F. Free Will / 4. For Free Will
1862
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However habituated you are, given time to ponder you can go against a habit
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1861
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The will is not compelled to move, even if pleasant things are set before it
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1856
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Nothing can be willed except what is good, but good is very varied, and so choices are unpredictable
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1849
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Since will is a reasoning power, it can entertain opposites, so it is not compelled to embrace one of them
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1853
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Because the will moves by examining alternatives, it doesn't compel itself to will
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16. Persons / F. Free Will / 5. Against Free Will
1854
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We must admit that when the will is not willing something, the first movement to will must come from outside the will
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17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
22105
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The human intellectual soul is an incorporeal, subsistent principle
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17. Mind and Body / A. Mind-Body Dualism / 4. Occasionalism
20700
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Without God's influence every operation would stop, so God causes everything
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18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
22108
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First grasp what it is, then its essential features; judgement is their compounding and division
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18. Thought / E. Abstraction / 1. Abstract Thought
10503
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We abstract forms from appearances, and acquire knowledge of immaterial things
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10509
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Understanding consists entirely of grasping abstracted species
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18. Thought / E. Abstraction / 2. Abstracta by Selection
10506
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Mathematics can be abstracted from sensible matter, and from individual intelligible matter
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18. Thought / E. Abstraction / 3. Abstracta by Ignoring
9094
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Mathematical objects abstract both from perceived matter, and from particular substance
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10505
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We can just think of an apple's colour, because the apple is not part of the colour's nature
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10504
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Abstracting either treats something as separate, or thinks of it separately
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10507
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Numbers and shapes are abstracted by ignoring their sensible qualities
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18. Thought / E. Abstraction / 8. Abstractionism Critique
9096
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The mind must produce by its own power an image of the individual species
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19. Language / C. Assigning Meanings / 3. Predicates
11206
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The mind constructs complete attributions, based on the unified elements of the real world
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20. Action / B. Preliminaries of Action / 2. Willed Action / a. Will to Act
23180
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The will is the rational appetite
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1846
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The will can only want what it thinks is good
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1847
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The will must aim at happiness, but can choose the means
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1857
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We don't have to will even perfect good, because we can choose not to think of it
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22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / g. Moral responsibility
1850
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Without free will not only is ethical action meaningless, but also planning, commanding, praising and blaming
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22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / b. Rational ethics
22112
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For humans good is accordance with reason, and bad is contrary to reason
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22. Metaethics / B. Value / 1. Nature of Value / e. Means and ends
22494
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We must know the end, know that it is the end, and know how to attain it
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22. Metaethics / C. The Good / 1. Goodness / g. Consequentialism
1851
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Good applies to goals, just as truth applies to ideas in the mind
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23. Ethics / C. Virtue Theory / 1. Virtue Theory / b. Basis of virtue
23181
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All acts of virtue relate to justice, which is directed towards the common good
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23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / d. Teaching virtue
8009
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Aquinas wanted, not to escape desire, but to transform it for moral ends [MacIntyre]
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23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / i. Absolute virtues
23182
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Legal justice is supreme, because it directs the other virtues to the common good
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23. Ethics / C. Virtue Theory / 3. Virtues / b. Temperance
22399
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Temperance prevents our passions from acting against reason
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23. Ethics / C. Virtue Theory / 3. Virtues / c. Justice
23177
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Justice directs our relations with others, because it denotes a kind of equality
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25. Social Practice / D. Justice / 1. Basis of justice
23179
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People differ in their social degrees, and a particular type of right applies to each
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25. Social Practice / D. Justice / 2. The Law / c. Natural law
22114
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Tyrannical laws are irrational, and so not really laws
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23174
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Natural law is a rational creature's participation in eternal law
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22113
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Right and wrong actions pertain to natural law, as perceived by practical reason
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25. Social Practice / E. Policies / 1. War / a. Just wars
7291
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For Aquinas a war must be in a just cause, have proper authority, and aim at good [Grayling]
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25. Social Practice / F. Life Issues / 3. Abortion
5508
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Aquinas says a fertilized egg is not human, and has no immortal soul [Martin/Barresi]
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26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / c. Matter as extension
16687
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Bodies are three-dimensional substances
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26. Natural Theory / C. Causation / 5. Direction of causation
11207
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A cause can exist without its effect, but the effect cannot exist without its cause
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26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
1859
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Even a sufficient cause doesn't compel its effect, because interference could interrupt the process
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27. Natural Reality / D. Time / 1. Nature of Time / f. Eternalism
15202
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Eternity coexists with passing time, as the centre of a circle coexists with its circumference
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28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
23178
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Divine law commands some things because they are good, while others are good because commanded
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28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
21251
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We can't know God's essence, so his existence can't be self-evident for us
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28. God / B. Proving God / 3. Proofs of Evidence / a. Cosmological Proof
5614
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If you assume that there must be a necessary being, you can't say which being has this quality [Kant]
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21269
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Way 1: the infinite chain of potential-to-actual movement has to have a first mover
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21270
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Way 2: no effect without a cause, and this cannot go back to infinity, so there is First Cause
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21271
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Way 3: contingent beings eventually vanish, so continuity needs a necessary being
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21272
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Way 4: the source of all qualities is their maximum, so something (God) causes all perfections
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28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
21273
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Way 5: mindless things act towards an obvious end, so there is an intelligent director
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29. Religion / B. Monotheistic Religion / 4. Christianity / a. Christianity
20211
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Life aims at the Beatific Vision - of perfect happiness, and revealed truth [Zagzebski]
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29. Religion / B. Monotheistic Religion / 4. Christianity / c. Angels
22106
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Aquinas saw angels as separated forms, rather than as made of 'spiritual matter' [Kretzmann/Stump]
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29. Religion / B. Monotheistic Religion / 4. Christianity / d. Heresy
16711
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Heretics should be eradicated like wolves
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29. Religion / D. Religious Issues / 2. Immortality / a. Immortality
23306
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Humans have a non-physical faculty of reason, so they can be immortal [Sorabji]
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1863
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If the soul achieves well-being in another life, it doesn't follow that I do
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29. Religion / D. Religious Issues / 2. Immortality / d. Heaven
4412
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Those in bliss have their happiness increased by seeing the damned punished
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29. Religion / D. Religious Issues / 3. Problem of Evil / a. Problem of Evil
21266
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God does not exist, because He is infinite and good, and so no evil should be discoverable
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21274
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It is part of God's supreme goodness that He brings good even out of evil
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