Empedocles of Acragas (or Akragas or Agrigentum), fl. mid-5th BC. One of the greatest of the Greek Presocratic thinkers, he put forth a view of the world as composed of four elements, earth, air, fire and water, whose relation to one another was governed by the principles of Love and Strife. He is generally considered either a "qualitative pluralist" or an Eleatic thinker.