Boethius was a sixth-century Roman senator and philosopher. He was unjustly accused of treason, and while awaiting execution, he wrote The Consolation of Philosophy. It is written as a dialogue with Lady Philosophy. Boethius concludes that despite the imperfections and evils of the world, there is a higher power and that happiness is possible.
Boethius was both a Platonist and a Christian, and he used natural philosophy to conclude that the mind is ultimately superior to the worldly evils of those seeking power and wealth. Happiness comes from within and is achieved by love, because God (Providence) rules the world through love. The mind and soul bring comfort in the face of worldly evil and seeming unfairness. All humans want happiness, which can’t ultimately be achieved by the earthly desires for wealth and power, as they are transitory and can never be completely fulfilled. Yet, this desire for happiness is universal, which means that it must come from God, and therefore the means of achieving it must also come from aligning with God.
In 1641, Descartes wrote The Meditations on First Philosophy, in Which is Proved the Existence of God and the Immortality of the Soul. He used skepticism to first reject beliefs based on authority or the senses, as they could both be wrong, as could reasoning. However, he does rely on his knowledge of existence: "I think, therefore I am." From this, he accepts that the mind exists and is immortal. He sees this as an innate idea, not based on the fallible senses. Also, God is an innate idea of Perfection, and the mind is led by the Perfect God to accept existence. Therefore, if the mind recognizes God, and God is perfect and won’t deceive the mind, then God exists.
That God is both a given and a conclusion is found in both philosophers. They both use logic to work from their starting points. For Boethius, the universal desire for happiness and its achievement both come from God. For Descartes, the recognition of existence comes from and proves the existence of God.