Karl Popper is well aware of the objections to which traditional rationalism is exposed, but he is not misled by these objections to pass to the other extreme, as are so many philosophers. The said objections were provoked by the oversimplifying theories of knowledge that had been suggested by the confidence in reason. Such philosophical claims of certain knowledge, untainted by error, were promoted in opposition to the claims of authority of the traditional scholastic doctrines, and became "the major inspiration of an intellectual and moral revolution without parallel in history." Popper highly values this very wholesome influence of the doctrine that truth is manifest. Nevertheless, he rejects the doctrine. Popper confronts his critical rationalism with the kind of rationalist epistemology which maintains that truth is manifest. These remarks concern Popper's opposition to the doctrine that truth is manifest, as this doctrine is embodied in the philosophies of Bacon and Descartes.