In life, we most often do not really know what we are doing, but still, most of the time we find our way. This involves many small “leaps”, or actions on based on assumptions that we don’t actually know are true. These are unavoidable, they are “reasonable”, and most of the time they are harmless.
In forming views of the world, we need the maturity to distrust systematic unity or strong coherence as a supposed accomplishment, while still pursuing it as a goal. (See also One, Many; Unity of Apperception; Error; Foundations?; Interpretation.)
If we have a concept of Reason as something well distinguished but still fundamentally open in the last instance — which I find especially clear and well developed in Aristotle, Brandom, and Ricoeur — then we have no need ever for Kierkegaardian irrational “great leaps” or arbitrary founding decisions in the style of Badiou.