Combining Texts

All the ideas for 'Theaetetus', 'Rules for the Direction of the Mind' and 'Introduction to Mathematical Logic'

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71 ideas

1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
Philosophers are always switching direction to something more interesting [Plato]
Clever scholars can obscure things which are obvious even to peasants [Descartes]
1. Philosophy / F. Analytic Philosophy / 2. Analysis by Division
Understanding mainly involves knowing the elements, not their combinations [Plato]
Either a syllable is its letters (making parts as knowable as whole) or it isn't (meaning it has no parts) [Plato]
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Most scholastic disputes concern words, where agreeing on meanings would settle them [Descartes]
2. Reason / A. Nature of Reason / 4. Aims of Reason
The secret of the method is to recognise which thing in a series is the simplest [Descartes]
2. Reason / A. Nature of Reason / 5. Objectivity
One truth leads us to another [Descartes]
2. Reason / A. Nature of Reason / 6. Coherence
A rational account is essentially a weaving together of things with names [Plato]
2. Reason / C. Styles of Reason / 3. Eristic
Eristic discussion is aggressive, but dialectic aims to help one's companions in discussion [Plato]
2. Reason / D. Definition / 4. Real Definition
A primary element has only a name, and no logos, but complexes have an account, by weaving the names [Plato]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Post proved the consistency of propositional logic in 1921 [Walicki]
Propositional language can only relate statements as the same or as different [Walicki]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
Boolean connectives are interpreted as functions on the set {1,0} [Walicki]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]
The empty set avoids having to take special precautions in case members vanish [Walicki]
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki]
Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki]
The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki]
Two infinite ordinals can represent a single infinite cardinal [Walicki]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / a. Units
I can only see the proportion of two to three if there is a common measure - their unity [Descartes]
Unity is something shared by many things, so in that respect they are equals [Descartes]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Inductive proof depends on the choice of the ordering [Walicki]
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
We master arithmetic by knowing all the numbers in our soul [Plato]
7. Existence / A. Nature of Existence / 3. Being / d. Non-being
Among the simples are the graspable negations, such as rest and instants [Descartes]
7. Existence / B. Change in Existence / 1. Nature of Change
There seem to be two sorts of change: alteration and motion [Plato]
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
If a word has no parts and has a single identity, it turns out to be the same kind of thing as a letter [Plato]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
A sum is that from which nothing is lacking, which is a whole [Plato]
The whole can't be the parts, because it would be all of the parts, which is the whole [Plato]
10. Modality / A. Necessity / 2. Nature of Necessity
Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
3+4=7 is necessary because we cannot conceive of seven without including three and four [Descartes]
11. Knowledge Aims / A. Knowledge / 1. Knowledge
Things are only knowable if a rational account (logos) is possible [Plato]
11. Knowledge Aims / A. Knowledge / 2. Understanding
Expertise is knowledge of the whole by means of the parts [Plato]
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
It is impossible to believe something which is held to be false [Plato]
11. Knowledge Aims / A. Knowledge / 4. Belief / d. Cause of beliefs
How can a belief exist if its object doesn't exist? [Plato]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
If we accept mere probabilities as true we undermine our existing knowledge [Descartes]
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
We all see intuitively that we exist, where intuition is attentive, clear and distinct rational understanding [Descartes]
When Socrates doubts, he know he doubts, and that truth is possible [Descartes]
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
Clear and distinct truths must be known all at once (unlike deductions) [Descartes]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / a. Innate knowledge
Our souls possess divine seeds of knowledge, which can bear spontaneous fruit [Descartes]
12. Knowledge Sources / B. Perception / 1. Perception
Perception is infallible, suggesting that it is knowledge [Plato]
Our senses could have been separate, but they converge on one mind [Plato]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
With what physical faculty do we perceive pairs of opposed abstract qualities? [Plato]
Thought must grasp being itself before truth becomes possible [Plato]
You might mistake eleven for twelve in your senses, but not in your mind [Plato]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
If someone had only seen the basic colours, they could deduce the others from resemblance [Descartes]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
An inadequate rational account would still not justify knowledge [Plato]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / a. Agrippa's trilemma
Parts and wholes are either equally knowable or equally unknowable [Plato]
Without distinguishing marks, how do I know what my beliefs are about? [Plato]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / a. Pro-internalism
A rational account might be seeing an image of one's belief, like a reflection in a mirror [Plato]
A rational account involves giving an image, or analysis, or giving a differentiating mark [Plato]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
Maybe primary elements can be named, but not receive a rational account [Plato]
The method starts with clear intuitions, followed by a process of deduction [Descartes]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / b. Pro-coherentism
A rational account of a wagon would mean knowledge of its hundred parts [Plato]
13. Knowledge Criteria / D. Scepticism / 5. Dream Scepticism
What evidence can be brought to show whether we are dreaming or not? [Plato]
13. Knowledge Criteria / E. Relativism / 6. Relativism Critique
If you claim that all beliefs are true, that includes beliefs opposed to your own [Plato]
Clearly some people are superior to others when it comes to medicine [Plato]
How can a relativist form opinions about what will happen in the future? [Plato]
15. Nature of Minds / A. Nature of Mind / 8. Brain
Nerves and movement originate in the brain, where imagination moves them [Descartes]
15. Nature of Minds / C. Capacities of Minds / 1. Faculties
Our four knowledge faculties are intelligence, imagination, the senses, and memory [Descartes]
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
The force by which we know things is spiritual, and quite distinct from the body [Descartes]
26. Natural Theory / A. Speculations on Nature / 4. Mathematical Nature
All the sciences searching for order and measure are related to mathematics [Descartes]
28. God / A. Divine Nature / 6. Divine Morality / c. God is the good
God must be the epitome of goodness, and we can only approach a divine state by being as good as possible [Plato]
29. Religion / D. Religious Issues / 3. Problem of Evil / a. Problem of Evil
There must always be some force of evil ranged against good [Plato]