1. (adj)positivist, rationalist someone who emphasizes observable facts and excludes metaphysical speculation about origins or ultimate causes Synonyms: positivist, rationalist
2. (adj)positivist, positivistic, positive of or relating to positivism Synonyms: cocksure, positive, prescribed, positivist, overconfident, electropositive, positively charged, irrefutable, convinced(p), incontrovertible, plus, positive(p), confirming, confident(p), positivistic