In the eighteenth century a powerful new case for skepticism was offered by the Scottish philosopher David Hume (1711–1776). Hume was an empiricist, claiming that all genuine ideas can be traced back to original impressions of sensation or introspective consciousness. Hume argued forcefully that on empiricist grounds there are no sound reasons for belief in God, an enduring self or soul, an external world, causal necessity, objective morality, or inductive reasoning. In fact, he argued that "Philosophy would render us entirely Pyrrhonian, were not Nature too strong for it." As Hume saw it, the real basis of human belief is not reason, but custom or habit. We are hard-wired by nature to trust, say, our memories or inductive reasoning, and no skeptical arguments, however powerful, can dislodge those beliefs. In this way, Hume embraced what he called a "mitigated" skepticism, while rejecting an "excessive" Pyrrhonian skepticism that he saw as both impractical and psychologically impossible.