The experience of pain is, due to its seeming universality, a very good portal through which to view various aspects of human life.
Two near contemporaries in the 18th and 19th centuries, Jeremy Bentham and the Marquis de Sade had very different views on these matters.
Michel Foucault, for example, observed that the biomedical model of pain, and the shift away from pain-inducing punishments, was part of a general Enlightenment invention of Man.
It is often accepted as a priori principle that one has inherent knowledge of one's own consciousness simply by virtue of dwelling within an "inner world" of the mind.
The experience of pain has been used by various philosophers to analyze various types of philosophy of mind, such as dualism, identity theory, or functionalism.