S
- Safety Condition for Knowledge
- Śāntideva
- Sānkhya
- Sablé, Marquise De
- Sadra, Mulla
- Santayana, George
- Sartre, Jean-Paul
- Schelling, F. W. J. von
- Schutz, Alfred
- Schopenhauer, Arthur
- Science, Karl Popper's Philosophy of
- Science, Metaphysics of
- Science, Philosophy of Social
- Science and Ideology
- Scientific Change
- Scientific Realism and Antirealism
- Scientific Representation
- Scotus, John Duns
- Self-Consciousness
- Self-Deception, Ethics and
- Sellars, Roy Wood
- Sellars, Wilfrid
- Semantic Conceptions of Logical Consequence
- Semantic Theory of Truth
- Semantics, Conceptual Role
- Semantics, Two-Dimensional
- Sen's Capability Approach
- Seneca, Lucius Annaeus
- Sengzhao (Seng-Chao)
- Sense-Data
- Sentential Logic
- Set Theory
- Sexuality, Philosophy of
- Shaftesbury, Earl of
- Shahrastānī, al-
- Sheffer Stroke
- Shpet, Gustav
- Sijistani, Abu Ya‘qub al-
- Simplicity in the Philosophy of Science
- Skeptical Theism
- Skepticism, Ancient Greek
- Skepticism, Cicero's Academic
- Skepticism, Contemporary
- Smith, Adam
- Social Contract Theory
- Social Science, Philosophy of
- Social Justice, Music and
- Socialism
- Socrates
- Solipsism and the Problem of Other Minds
- Solovyov, Vladimir
- Sophists
- Soundness, Validity and
- Spencer, Herbert
- Spinoza, Benedict
- Square of Opposition
- Stanton, Elizabeth Cady
- Stephen, Leslie
- Stilpo
- Stirling, James Hutchison
- Stoicism
- Structuralism, Mathematical
- Suarez, Francisco
- Substance, 17th Century Theories of
- Supervenience and Determination
- Supervenience and Mind
- Surrogate Parenting
- Surveillance Ethics
- Sympathy and Empathy in Ethics
- Symposium
- Synderesis
- Synesthesia
