Ideas of Alvin Plantinga, by Theme

[American, b.1932, Based at the University of Michigan, Calvin College, then at Notre-Dame.]

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5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
Maybe proper names involve essentialism
6. Mathematics / A. Nature of Mathematics / 3. Numbers / g. Real numbers
Could I name all of the real numbers in one fell swoop? Call them all 'Charley'?
7. Existence / A. Nature of Existence / 3. Being / a. Nature of Being
Necessary beings (numbers, properties, sets, propositions, states of affairs, God) exist in all possible worlds
7. Existence / A. Nature of Existence / 3. Being / d. Non-being
Plantinga proposes necessary existent essences as surrogates for the nonexistent things
9. Objects / A. Existence of Objects / 4. Individuation / a. Individuation
The 'identity criteria' of a name are a group of essential and established facts
9. Objects / A. Existence of Objects / 4. Individuation / d. Individuation by haecceity
Surely self-identity is essential to Socrates?
'Being Socrates' and 'being identical with Socrates' characterise Socrates, so they are among his properties
A snowball's haecceity is the property of being identical with itself
9. Objects / D. Essence of Objects / 1. Essences of Objects
Socrates is a contingent being, but his essence is not; without Socrates, his essence is unexemplified
9. Objects / D. Essence of Objects / 2. Types of Essence
Does Socrates have essential properties, plus a unique essence (or 'haecceity') which entails them?
9. Objects / D. Essence of Objects / 9. Essence and Properties
An object has a property essentially if it couldn't conceivably have lacked it
X is essentially P if it is P in every world, or in every X-world, or in the actual world (and not P elsewhere)
Properties are 'trivially essential' if they are instantiated by every object in every possible world
If a property is ever essential, can it only ever be an essential property?
Essences are instantiated, and are what entails a thing's properties and lack of properties
9. Objects / F. Identity among Objects / 5. Self-Identity
Does 'being identical with Socrates' name a property? I can think of no objections to it
10. Modality / A. Necessity / 4. De re / De dicto modality
Expressing modality about a statement is 'de dicto'; expressing it of property-possession is 'de re'
'De dicto' true and 'de re' false is possible, and so is 'de dicto' false and 'de re' true
Can we find an appropriate 'de dicto' paraphrase for any 'de re' proposition?
'De re' modality is as clear as 'de dicto' modality, because they are logically equivalent
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
We can imagine being beetles or alligators, so it is possible we might have such bodies
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
Asserting a possible property is to say it would have had the property if that world had been actual
Possible worlds clarify possibility, propositions, properties, sets, counterfacts, time, determinism etc.
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
Plantinga says there is just this world, with possibilities expressed in propositions
Plantinga's actualism is nominal, because he fills actuality with possibilia
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
A possible world is a maximal possible state of affairs
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
What Socrates could have been, and could have become, are different?
If possible Socrates differs from actual Socrates, the Indiscernibility of Identicals says they are different
It doesn't matter that we can't identify the possible Socrates; we can't identify adults from baby photos
If individuals can only exist in one world, then they can never lack any of their properties
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
Possibilities for an individual can only refer to that individual, in some possible world
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
The counterparts of Socrates have self-identity, but only the actual Socrates has identity-with-Socrates
Counterpart Theory absurdly says I would be someone else if things went differently
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
Maybe a reliable justification must come from a process working with its 'proper function'
18. Thought / D. Concepts / 6. Abstract Concepts / a. Abstract concepts
The idea of abstract objects is not ontological; it comes from the epistemological idea of abstraction
Theists may see abstract objects as really divine thoughts
19. Language / C. Semantics / 5. Possible Worlds Semantics
Plantinga has domains of sets of essences, variables denoting essences, and predicates as functions
Plantinga's essences have their own properties - so will have essences, giving a hierarchy
19. Language / E. Propositions / 2. Nature of Propositions
Are propositions and states of affairs two separate things, or only one? I incline to say one
Propositions can't just be in brains, because 'there are no human beings' might be true
If propositions are concrete they don't have to exist, and so they can't be necessary truths
29. Religion / F. Problem of Evil / 2. Human Evil
Moral evil may be acceptable to God because it allows free will (even though we don't see why this is necessary)
29. Religion / F. Problem of Evil / 4. Natural Evil
It is logically possible that natural evil like earthquakes is caused by Satan