French philosopher Rene Descartes’s Discourse on Method and Meditations on First Philosophy constitute two halves of a single unified project. The former was first published in 1637, while the latter was first published in 1641. The full title of Discourse on Method is Discourse on the Method of Rightly Conducting One's Reason and of Seeking Truth in the Sciences. The full title of Mediations on First Philosophy is Meditations on First Philosophy in which the existence of God and the immortality of the soul are demonstrated.

In his Discourse on Method, Descartes offers autobiographical background to give the reader a sense of what led him to undertake the kind of investigations that are to be found in the Meditations. The Discourse on Method itself provides an overall summary of Descartes’s concerns with the nature of the human mind and the existence or non-existence of God, and highlights the expansive range of his academic interests, including art, literature, mathematics, and physics, to name but a few.

Through this autobiographical reconstruction of the philosophical view Descartes came to adopt, he highlights how two drastically different experiences—his time at university and his time travelling and interacting with everyday persons—led him to the same conclusion: that there seemed to be a lack of consensus and certainty as to the true value of what an individual believes.

Regarding academia, says Descartes, what became apparent was the fact that despite the history of philosophy containing some of the greatest minds in the history of humanity, it was a history of a discipline that was more divided than united. This splintering characterized a proliferation of views on a given issue, rather than a progressive unity of resolved problems.

Regarding the time Descartes spent travelling around Europe, what became apparent was the fact that it is the norm for people to be less likely of telling you why they hold a certain opinion to be true (e.g. does God exist or not exist?) and are more likely to simply state what they believe as truth.

From these two experiences, Descartes arrived at his conclusion: the only possible means of uncovering what is absolutely and objectively true cannot be found in conversation with everyday people nor in the halls of the university system. The only way forward was to subject every belief to doubt and scrutiny in order to find out whether there were some ideas we have that can be said to be true beyond any possible doubt.

Given this background, it is in Descartes’s Meditations on First Philosophy that readers are able to grasp the full extent of his endeavor. The First Meditation begins by formalizing the experiences documented in his Discourse on Method and boldly argues that it is only by doubting everything that we can ever be certain of anything. The Second Meditation shows how we can be certain that we exist even if everything else is put into doubt. The Third Meditation demonstrates that not only do we exist, but that God exists as well. The Fourth Meditation identifies the sources of our errors in the illegitimate use of our reason, while the Fifth and Sixth Meditations conclude by reestablishing, with absolute certainty, the existence of things and the material world.