From the comments:
All reason must assume (without question!) a basis of innate common sense.
Because the reasoning we use to discriminate between assumptions itself has assumptions.
There is no rational basis for reason: yes, this is obvious, but ignored.
This never used to be a problem for philosophers (in the ancient world and up to Aquinas), since they implicitly accepted that humans are 'born into the world' equipped with valid means of understanding the world.
(And humans are thus equipped not by accident. Teleology, purpose is assumed, is part of common sense.)
But later philosophers (notably Descartes) created a pseudo- and insoluble problem by doubting 'everything' (as they imagined they were doing), by trying to work from arbitrary and assumption-free axioms, or by using reason to evaluate reason.
And instead of retreating from their error (which led to reductio ad absurdum in every direction), they simply went further and further along the same path, seeking coherence at some more advanced and specialized level - and here we are...
The point is that philosophical enquiry as such has already left-out a lot, even before it starts; and therefore all philosophy is distorted and wrong when pushed hard enough. At the bottom is 'common sense'/ Natural Law / the human condition - and then, for some, divine revelation.
The validity of divine revelation being itself established by common sense/ natural law kinds of reasoning and knowledge - and *not* by specialist sub-systems such as philosophy or science.
This is where Pascal's Pensees are so impressive - not because of his 'wager' but because he establishes 1. the validity and 2. the superiority of Christianity using common sense reasoning - for example the miracles and prophecies.
All that is required for Pascal to be compelling is an acknowledgement of the *possibility* of divine revelation, soul, God etc. (i.e.the standard ingredients of religious thinking).
The root reason why modern atheists are incredulous about Christianity is that they (and my former self) deny the *possibility* of the soul, the supernatural, God/ gods, revelation, miracles, prophecies etc.
And to deny these is to deny both common sense and the wisdom of the ages - to set-up oneself and one's era and one's culture as qualitatively superior to all of human history and four fifths of the rest of the world.
The foundational sin of modernity is therefore pride (the worst of sins) - the assertion of existential self-sufficiency.
Ironically, this infinite pride and exponential subversion and insatiable destruction presents itself to itself as humility, as innocent enquiry, as: 'What do I know? I only want to find-out! I only want to be sure."