Socrates' Children: Ancient Philosophers by Peter Kreeft

Socrates' Children

(Des Plaines: Word on Fire, 2023), 183

I had been looking for a summary of philosophy, and I couldn't ask for a better source than Peter Kreeft and Word on Fire. Kreeft is characteristically fun, concise, and incisive. Next up I'm reading some of Plato's Dialogues, starting with Apology.




A Very Short Introduction to Philosophy

  • "Philosophy begins in wonder and ends in wisdom."
  • The four divisions of philosophy are:
    • Metaphysics - what is real?
    • Philosophical anthropology - what am I?
    • Epistemology - How can I know?
    • Ethics - What should I do?
  • Everyone has a philosophy

Do-It-Yourself Course in Philosophy

Introduction to Ancient Philosophy

The Sages


What is the meaning of life? Nothing. All is vanity.

  • Ecclesiastes is a work of philosophy asking: What is the meaning of life?
    • Nothing (nihilism). All is vanity.
  • This question (and answer) is included in the Bible as part of the rabbinic confrontational teaching method (similar to the Socratic method)


Monotheistic dualism between good and evil

Shankara ★

The Hindu Thomas Aquinas

  • Vedas: mythical and poetical
  • Upanishads: philosophical—reality is absolutely single: all things are appearances of one reality
    • Brahman is the impersonal, eternal, divine Mind, transcending all dualities
  • Bhagavad-Gita: practical and personal

Gotma the Buddha ★

The man who woke up: enlightenment through the extinguishing of desire

  • Middle way between self-indulgence and self-mortification
  • Four Noble Truths:
    • To live is to suffer
    • The cause of suffering is desire
    • The way to the extinction of suffering is the extinction of desire
    • The way to extinguish desire is the Noble Eightfold Path
  • Where Aristotle discovered the essential logical form of all theoretical thinking, Buddha did the same for practical thinking


The Socrates and Aristotle of China

  • Man is not born either good or evil, but able to be good by being trained and taught rightly
  • Virtue ethics

Lao Tzu

Tao—the way

  • Suppleness rather than rigidity is the ideal
  • The Tao The Ching is the most translated book in the world after the Bible, and has striking similarities to the Sermon on the Mount

Mo Tzu

Universal love

Jesus ★★★

He is the end and object of all philosophy

The Greeks (and a few Romans)

  • "Almost everything of lasting value in Western civilization comes from either the Jews or the Greeks."

Thales of Miletus

The first to ask: What is everything? (Water)

  • Thales took the first step in philosophy.


What is everything? The infinite.


What is everything? Air.


All things are numbers.

  • Discovered that nature obeyed mathematical laws and math is the very "language of nature"
  • Believed the cosmos was a giant musical instrument designed to play the "music of the heavenly spheres"

Heraclitus ★

Everything changes.

  • Everything is made of fire, and the cosmos is at war
  • All things change, and there is a Logos (law) of change
  • This Logos also governs all human affairs
  • "One's metaphysics always determines one's ethics. Practice always presupposes theory." (58)


First philosophical theologian

  • He reasoned his way to a monotheism against the polytheism of his peers
  • Kreeft: Read with a dictionary at hand: "Minds are only as big as their ideas, and ideas live only in idea-houses, which are words." (59)

Parmenides ★

Only Being is; nonbeing cannot be.

  • He is the opposite of Heraclitus. Instead of everything flows, nothing flows
  • The contrast between Heraclitus and Parmenides shaped the whole history of Western philosophy.
  • He follows reason rather than the senses: pure rationalism with no concession to empiricism

Zeno of Elea

Pure logic, but reduced to ridiculousness

  • Zeno's paradoxes are reductio ad absurdum arguments; they are logical absurdities where logic disproves the testimony of the senses


Earth, air, fire, water

  • Reality composed of four elements: earth, air, fire, water
  • "Who is more pitiable: the modern person who can no longer see the whole, or the premodern person who has not yet clearly distinguished the parts?" (71)


Explanation by Mind, not just matter

Democritus ★

The first materialist

  • He was a materialist and created a theory of atoms
  • Kreeft gives a lengthy critique of Materialism (and later adherents like Hobbes, Marx, and Descartes)
    • "Scientism is not scientific enough"
    • The problem with materialist metaphysics is the ethics and atheism it implies


Popularized Democritus' materialism in "On the Nature of Things"

Protagoras and the Sophists ★

"Man is the measure of all things." Morality is not natural but conventional.

  • The Sophists were the first to look inward and turn the attention of philosophy to the man
  • The Sophists were skeptics in epistemology, relativists in ethics, and subjectivists in both
  • Kreeft enumerates some problems of relativism
  • The Sophists asked questions of ethics, and pioneered the dialectical method of asking questions from both sides of an issue

Gorgias the Sophist

There is no being, no knowledge of it, and no way to communicate it

Socrates ★★

Know thyself

  • Socrates was the second most important and influential person who ever lived next to Jesus
  • Every school of ancient philosophy after Socrates claims to be the authentic interpretation of Socrates
  • Your identity is in your soul
  • Socrates argued for objective reality against the Sophists moral relativism and subjectivism
  • Socrates' Teachings
    • Know thyself: anthropology is the key to philosophy
    • To know the human self, you must know its telos: ethics is the key to anthropology
    • The greatest good is virtue
    • The true self is the soul
    • The soul is immortal
    • No evil can happen to a good man in this world or the next
    • The cause of evil is ignorance; wisdom is the key to all the virtues
    • Virtue can be taught
    • Knowledge of true values is innate in us
    • Philosophy seeks the truth, the essential natures

Plato ★★

The Good measures man; man does not measure the Good

  • "The Dialogues of Plato are the classics of the classics. They are to philosophy what the Bible is to religion."
    • Summary of the dialogues on 111
    • "Every bookcase (and every mind!) should have these dialogues in it."
    • "You have to take time with his dialogues"
  • Read The Republic Book 7 to learn about the Quadrivium and Trivium (cf. The Lost Tools of Learning)
  • Plato's Theory of Forms: forms exist outside the mind and are the objects sought by thinking; they are a third kind of reality besides matter and mind
    • Plato's Cave
  • The Republic centers on the four cardinal Virtues of justice, wisdom, courage, and moderation


The Philosopher. The archetype of well-rounded common sense.

  • Logic seeks clarity, truth, and proof
  • Three acts of the mind: conceiving (understanding), judging, and reasoning by induction (many particular to a general) or deduction (from a general principle to a particular conclusion)
  • The Four Causes:
    • Material cause: What is it made of?
    • Formal cause: What is it made into? What is its essential nature?
    • Efficient cause: Where did it come from?
    • Final cause: Where is it going to? What is its end?
  • Book 1 of MetaphysicsI is the first history of philosophy
  • Aristotle's solution to the problem of change is Hylomorphism: matter and form are separate
    • Change is the actualization of potentiality
  • Aristotle's Outline of Everything:
    • Nonbeing
    • Being
      • Accidents (nine of them)
      • Substances
        • Spiritual substances (gods, angels)
        • Material substances
          • Nonliving (inorganic minerals)
          • Living (organisms)
            • Plants (no sensations)
            • Animals (sensations)
              • Irrational animals (brutes)
              • Rational animals (humans)
  • Aristotle's metaphysics:
    • There must exist one supreme, first, uncaused cause or unmoved mover
    • Everything that is in motion is moved by something else, and the universe as a whole is in motion; therefore, the universe as a whole is moved by something else.
  • Aristotle's anthropology:
    • Man is a rational animal
    • The human soul has three levels of powers (faculties): vegetative, sensory, and rational
    • Man has free will
    • Did not believe that man had an immortal individual soul
  • Aristotle's epistemology:
    • Aristotle is a "soft empiricist": all human knowledge begins with the senses but is not limited by them
    • Words reflect concepts in understanding, which reflect forms. Logos means word (language), thought (concept), and form (intelligible essence)
    • Aristotle defined truth simply as thinking and saying what is: "If one says of what is that it is, or of what is not that it is not, he speaks the truth, but if he says of what is that it is not, or of what is not that it is, he does not speak the truth." (144, cf. transgenderism)
    • Aristotle distinguishes knowledge from opinion and certainty from probability, while refuting skepticism.
  • Aristotle's ethics:
    • Three ethical concepts: the good, the right, and the ought. Good is the object of desire (Nicomachean Ethics)
    • Ends are desired for themselves; Means are desired for the sake of other things.
    • The end of ends, the greatest good, the summum bonum, is happiness (eudaimonia). Moral virtue is what is needed to reach eudaimonia.
    • Human happiness is something we do: "activity of the soul according to virtue in a complete life"
    • Virtue (arête) is excellence. A virtue is a good habit, which is acquired by practice, which is why moral education is important.
    • Virtue consists of both intellectual virtues and moral virtues (cardinal virtues)
    • Friendship is necessary for happiness ("Such typically Aristotelian common sense can wonderfully simplify your life!")
    • Perfect happiness is the contemplation of eternal truth
  • Aristotle's politics:
    • Man is a political animal (family, tribe, state)
    • The basic political virtue is justice: giving each his due. But friendship surpasses justice.
    • A good state may be run by different arrangements of government, but is one that attains the end of the common good, the happiness of its people.
    • Aristotle preferred Democracy: the least bad but also the least good. Monarchy can be the best, but it is often the worst.
    • Moral education is the most important cause of good government.

Pyrrho and Skepticism

The founder of skepticism

  • Pyrrho's ideas:
    • Nobody knows anything real, really. Certainty is impossible and we should suspend judgment in all cases.
    • The greatest good is ataraxia: inner peace and tranquility.
  • "Every school of philosophy seems to have taken one point from Socrates and left the rest behind." (153)
  • Kreeft gives a critique of Skepticism: it seems self-contradictory (skeptical of itself)
    • "The happiness promised by skepticism is a rather low, pale, and boring one." (154)

Diogenes the Cynic and Cynicism

Cynicism: life should be simple

  • Cynicism: virtue is the only good, and all the things society prizes are worthless
  • "The only good thing money could not buy is poverty."

Epicurus and Epicureanism (Hedonism) ★

The supreme good and purpose of life is pleasure

  • Epicurus' hedonism called for a careful, prudent, rational assessment of pleasures and the self-discipline to reject present pleasures if they would cause future pains (delayed gratification or Time preference)
  • Hedonism is subjective, because pleasures are subjective
  • Epicurus identified the three problems of death, divine intervention, and fate
  • Kreeft gives a critique of Epicureanism: it fails to account for and motivate anyone to pursue a life of moral heroism, and is a paradox (the harder you try to be happy through pleasures, the unhappier you become)

Epictetus and Stoicism ★

Gives the succinct summary of Stoicism

  • Stoicism
    • A practical ethics: Men are disturbed not by things but by the view they take of things. You are responsible for your own happiness.
    • "Serenity prayer" is stoic
    • Kant was the most famous Stoic philosopher of all time
  • Kreeft gives a critique of Stoicism:
    • Thinking cannot discover real goods → weakens morality
    • It destroys personal sympathy


A classical Stoic

  • Anger is the worst of all passions because it is the hardest to control
  • Gratitude is crucial to human relationships
  • The will is the master of the soul

Marcus Aurelius

History's only successful philosopher-king

  • The Meditations is his eminently popular guidebook of practical Stoic wisdom


Lover of natural law and the greatest orator of all time

  • The greatest orator of all time and the greatest master of the Latin language
  • Defended the old republicanism while Rome was transitioning to empire
  • Transmitted the Platonic and Aristotelian notion of a natural moral law, and concluded that all citizens have innate human rights

Plotinus and Neoplatonism ★

The last ancient philosopher who synthesized his predecessors

  • Spirit vs matter: our end is to escape from matter and the body
  • Being is the cosmic drama of exile and return: the meaning of life is to fly upward away from matter to the One

Topic: Philosophy


  • Easter 2023


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Created: 2023-04-04-Tue
Updated: 2023-08-19-Sat