Modernism: Modern philosophy is construed as beginning sometime in the Renaissance. A philosophy that seeks new foundations for knowledge was offered as an alternative to that provided by the ancient philosophers. Modern Philosophy was presented as starting afresh from new beginnings - turning to nature directly (Francis Bacon), turning to the mind directly (Rene Descartes), turning to experience directly (Thomas Hobbes).
Postmodernism: Of or relating to a complex set of reactions to modern philosophy and its presuppositions, as opposed to the kind of agreement on substantive doctrines of philosophical questions that often characterizes a philosophical movement. Although there is little agreement on precisely what the presuppositions of modern philosophy are, and disagreement on which philosophers exemplify these presuppositions, postmodern philosophy typically opposes foundationalism, essentialism, and realism.