By a variety of ways, some outside of the orbits of Post Enlightenment rationalism.
From a Christian perspective we would argue that mind alone is insufficient to adequately understand non physical reality Metaphysics), something of course which rationalism rejects as either non existent (it can't be proved) or unknowable (i.e an agnostic position).
Christians claim otherwise. There is a paradigm in the Eden story. Two trees, one representing life, the other the knowledge of good and evil. Fallen humanity lives from the latter, in the realm of moral legalism and rationalism, as in fact do many Christians. Traditional systematic theology and apologetics are based on that paradigm, self sufficient knowledge.
But the tree of life requires revelation, something beyond the natural capacity of the human mind. This is why Jesus never gave a systematic presentation in response to Pilate's question "What is truth?" but instead stated "I am Truth". Christian epistemology is based on three foundations, love, faith had hope, all relational terms founded in God's revelation to us supremely in Christ.
1 Cor 13:12-13 Now I know in part; then I shall know fully, even as I am fully known. And now these three remain: faith, hope and love. But the greatest of these is love.
John
NZ
This is not to decry science and genuine intellectual endeavour. But it does limit their sphere of authority. Rationalism demands proof, even of God, and is either agnostic or atheistic about the supernatural. Augustine understood this, picking up on Jesus' teaching when he said we must believe in order to know. This is true both of God and of another person. Some knowledge relies on relationship.