Truth and the good: why do we do evil? / Socrates
Being and non-being: what is real? / Parmenides of Elea
Change, conflict and harmony: how does the cosmos work? / Heraclitus of Ephesus
The good and the just: what is the source of truth? / Plato
Life in accordance with nature: can it make us happy? / Epictetus of Hierapolis
Knowledge and belief: can we know anything? / Sextus Empiricus
God and man: what is evil? / St Augustine
God's necessity: could God not exist? / St Anselm
Knowledge, faith and the soul: is the world good? / St Thomas Aquinas
What there is: do ideas exist? / William of Ockham
God, the world and our minds: how can we achieve certainty? / René Descartes
The nature of God: do we have free will? / Benedict Spinoza
God and the world: why is there something rather than nothing? / Gottfried Wilhelm Leibniz
Faith: why should we believe? / Blaise Pascal
Reason, freedom and equality: what did God endow us with? / John Locke
Perception and causality: what can we know? / David Hume
Reason, necessity and morality: how is knowledge possible? / Immanuel Kant
History and the absolute: progress without good and evil? / Georg Wilhelm Friedrich Hegel
World, will and sex: should we commit suicide? / Arthur Schopenhauer
God and faith: do we need the church? / Sören Aabye Kierkegaard
The will to power: is there good and evil? / Friedrich Nietzsche
Consciousness and evolution: what is the human spirit? / Henri Bergson
The foundations of certainty: what can we know and how can we know it? / Edmund Husserl.
