Knowledge, Theory of Reason 7 Truth 6 Belief and doubt 5 Epistemology 5 Philosophy 5 Causation 4 Classification 4 Information organization 4 Philosophy, Indic 4 Science 4 Ethics 3 History 3 Induction (Logic) 2 Knowledge, Sociology of 2 Language and logic 2 Metaphysics 2 Methodology 2 Perception 2 Perplexity (Philosophy) 2 Philosophy of mind 2 Prediction (Logic) 2 Questioning 2 Realism 2 Social epistemology 2 Act (Philosophy) 1 Analysis (Philosophy) 1 Artificial intelligence 1 Biology 1 Commitment (Psychology) 1