In Heaven, one must simply come to terms with the fact that mortals cannot understand everything they see. For Dante, this means trusting to faith. The empirical logic, based on the senses, by which Dante has reasoned so far, does not get him far in Heaven. One miracle that must constantly be taken on faith is that two bodies can occupy one space, a prelude for the mystery of the Incarnation – that Christ can simultaneously be man and God. Finally, Dante defines faith as both a "substance for things we hope for" and "evidence of things not seen." The Scriptural source is faith in the Holy Ghost.
Despite his heavy emphasis on faith, Dante in Paradiso explains many seemingly contradictory or impossible facts in a logical manner; it follows that faith has little practical function in Paradiso.
Although Dante logically explains many seemingly contradictory or impossible facts in Paradiso, his theologically based logic comes to an end when confronted with the mystery of the Incarnation; this mystery and its various foils in Paradiso are the sole reason Dante relies on faith.