"Democritus of Abdera " (details from "Democritus of Abdera or Democrito "), 1635 Peter Paul Rubens (1577-1640) Prado Museum, Madrid, Spain

Known as the "laughing philosopher", Democrito or Democritus of Abdera advanced mechanistic views of the universe (atomic theory) and felt that all that was, was the best that could be. He also felt that "chance" did not exists because accepting such would imply ignorance of cause. 

Depictions of Democritus are often paired with those of Heraclitus (the crying philosopher) as representing polar opposites of human nature - optimism vs. pessimism.