Combining Texts

All the ideas for 'Mahaprajnaparamitashastra', 'What are Sets and What are they For?' and 'Introduction of 'Essence of Christianity''

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19 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
The empty set is something, not nothing! [Oliver/Smiley]
     Full Idea: Some authors need to be told loud and clear: if there is an empty set, it is something, not nothing.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 1.2)
     A reaction: I'm inclined to think of a null set as a pair of brackets, so maybe that puts it into a metalanguage.
We don't need the empty set to express non-existence, as there are other ways to do that [Oliver/Smiley]
     Full Idea: The empty set is said to be useful to express non-existence, but saying 'there are no Us', or ¬∃xUx are no less concise, and certainly less roundabout.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 1.2)
The empty set is usually derived from Separation, but it also seems to need Infinity [Oliver/Smiley]
     Full Idea: The empty set is usually derived via Zermelo's axiom of separation. But the axiom of separation is conditional: it requires the existence of a set in order to generate others as subsets of it. The original set has to come from the axiom of infinity.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 1.2)
     A reaction: They charge that this leads to circularity, as Infinity depends on the empty set.
Maybe we can treat the empty set symbol as just meaning an empty term [Oliver/Smiley]
     Full Idea: Suppose we introduce Ω not as a term standing for a supposed empty set, but as a paradigm of an empty term, not standing for anything.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 1.2)
     A reaction: This proposal, which they go on to explore, seems to mean that Ω (i.e. the traditional empty set symbol) is no longer part of set theory but is part of semantics.
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
The unit set may be needed to express intersections that leave a single member [Oliver/Smiley]
     Full Idea: Thomason says with no unit sets we couldn't call {1,2}∩{2,3} a set - but so what? Why shouldn't the intersection be the number 2? However, we then have to distinguish three different cases of intersection (common subset or member, or disjoint).
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 2.2)
5. Theory of Logic / G. Quantification / 6. Plural Quantification
If you only refer to objects one at a time, you need sets in order to refer to a plurality [Oliver/Smiley]
     Full Idea: A 'singularist', who refers to objects one at a time, must resort to the language of sets in order to replace plural reference to members ('Henry VIII's wives') by singular reference to a set ('the set of Henry VIII's wives').
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], Intro)
     A reaction: A simple and illuminating point about the motivation for plural reference. Null sets and singletons give me the creeps, so I would personally prefer to avoid set theory when dealing with ontology.
We can use plural language to refer to the set theory domain, to avoid calling it a 'set' [Oliver/Smiley]
     Full Idea: Plurals earn their keep in set theory, to answer Skolem's remark that 'in order to treat of 'sets', we must begin with 'domains' that are constituted in a certain way'. We can speak in the plural of 'the objects', not a 'domain' of objects.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], Intro)
     A reaction: [Skolem 1922:291 in van Heijenoort] Zermelo has said that the domain cannot be a set, because every set belongs to it.
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Logical truths are true no matter what exists - but predicate calculus insists that something exists [Oliver/Smiley]
     Full Idea: Logical truths should be true no matter what exists, so true even if nothing exists. The classical predicate calculus, however, makes it logically true that something exists.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 5.1)
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / g. Applying mathematics
If mathematics purely concerned mathematical objects, there would be no applied mathematics [Oliver/Smiley]
     Full Idea: If mathematics was purely concerned with mathematical objects, there would be no room for applied mathematics.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 5.1)
     A reaction: Love it! Of course, they are using 'objects' in the rather Fregean sense of genuine abstract entities. I don't see why fictionalism shouldn't allow maths to be wholly 'pure', although we have invented fictions which actually have application.
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Sets might either represent the numbers, or be the numbers, or replace the numbers [Oliver/Smiley]
     Full Idea: Identifying numbers with sets may mean one of three quite different things: 1) the sets represent the numbers, or ii) they are the numbers, or iii) they replace the numbers.
     From: Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 5.2)
     A reaction: Option one sounds the most plausible to me. I will take numbers to be patterns embedded in nature, and sets are one way of presenting them in shorthand form, in order to bring out what is repeated.
18. Thought / A. Modes of Thought / 5. Rationality / a. Rationality
When absorbed in deep reflection, is your reason in control, or is it you? [Feuerbach]
     Full Idea: When, submerged in deep reflection, you forget both yourself and your surroundings, is it you who controls reason, or is it rather reason that controls and absorbs you?
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], I)
     A reaction: A delightful question, even if it looks like a false dichotomy. I'm not sure what to make of 'me', if my reason can be subtracted from it. Aquinas was one the same wavelength here.
22. Metaethics / C. The Good / 1. Goodness / b. Types of good
Reason, love and will are the highest perfections and essence of man - the purpose of his life [Feuerbach]
     Full Idea: Reason, love and power of will are perfections of man; they are his highest powers, his absolute essence in so far as he is man, the purpose of his existence. Man exists in order to think, love and will.
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], I)
     A reaction: Feuerbach was a notable atheist, but adopts a religious style of language which modern atheists would find rather alien. Personally I love talk of ideals and perfections. Ideals have been discredited in modern times, but need a revival.
23. Ethics / C. Virtue Theory / 3. Virtues / a. Virtues
The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna]
     Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom.
     From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88)
     A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate').
27. Natural Reality / G. Biology / 5. Species
Consciousness is said to distinguish man from animals - consciousness of his own species [Feuerbach]
     Full Idea: What constitutes the essential difference between man and animal? The most simple, general, and most widely held answer to this question is consciousness. Consciousness is given only in the case of a being to whom his species ...is an object of thought.
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], I)
     A reaction: Rather speculative. Since other species cohabit and breed only with their fellow species members, one might have thought they were aware of them.
28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
A God needs justice, kindness and wisdom, but those concepts don't depend on the concept of God [Feuerbach]
     Full Idea: The concept of God depends on the concepts of justice, kindness and wisdom - a God who is not kind, not just, and not wise is no God. But these concepts do not depend on the concept of God. That a quality is possessed by God does not make it divine.
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], II)
     A reaction: This is part of Feuerbach's argument for atheism, but if you ask for the source of our human concepts of justice, kindness and wisdom, no one, I would have thought, could cite God for the role.
28. God / C. Attitudes to God / 4. God Reflects Humanity
The nature of God is an expression of human nature [Feuerbach]
     Full Idea: God is the manifestation of man's inner nature, his expressed self.
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], II)
     A reaction: Even if you are a deeply committed theist, you have to concede some of this point. The perfections attributed to God are usually of human qualities. Leibniz, though, says that God has an infinity of perfection, mostly unknown to us.
28. God / C. Attitudes to God / 5. Atheism
If love, goodness and personality are human, the God who is their source is anthropomorphic [Feuerbach]
     Full Idea: If love, goodness, and personality are human determinations, the being which constitutes their source and ...their presupposition is also an anthropomorphism; so is the existence of God.
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], II)
     A reaction: It is certainly a struggle for the imagination to grasp a being which is characterised by idealised versions of human virtues, and yet has an intrinsic nature which is utterly different from humanity.
29. Religion / D. Religious Issues / 1. Religious Commitment / a. Religious Belief
Religion is the consciousness of the infinite [Feuerbach]
     Full Idea: Religion is the consciousness of the infinite.
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], I)
Today's atheism will tomorrow become a religion [Feuerbach]
     Full Idea: What is regarded as atheism today will be religion tomorrow.
     From: Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], II)
     A reaction: Modern critics of atheism frequently accuse it of being a new religion. I doubt whether Feuerbach is right, but it is a nice provocative idea.