Mutual, mutable, mutate and mutant are all derived from the same Latin root, mutare, to change.
Mutual comes from Middle French mutuel, from Latin mutuus — lent, borrowed. Mutable, from Middle English, from Latin mutabilis.
Why should anyone care about this etymological bit of trivia? For me, the profoundest value of entering a relationship of mutuality — of that sacred acknowledgment of thou, of namaste, of the gassho gesture — is its transformative power, which is the most powerful demonstration that otherness is transcendent, real, relevant and radically surprising.
Speaking of etymologies, surprise has a surprising etymology: sur, super + prise, take, derived from prendre. Prendre is also the root of comprise and comprehend, to together-take. Surprise is the eversion (the flipping inside-out) of comprise — to be taken by what is super, beyond, above.
To remain alert to what always transcends any particular comprehension is a kind of everted comprehension that complements every comprehension with expectation of potentially disruptive always-more — I want to call that suprehension.
Comprise : surprise :: comprehend : suprehend
Suprehension is a vectoral state of awareness toward a permanent possibility of radical shock, a something that will change everything, which is the prize of mutuality.
Suprehension is fallibilism, but intensified, charged with positive value and religious significance.
Suprehension is knowledge placed in the context of infinity as qualitative fact.
(Infinity as qualitative fact means infinity produces novel categories that have never before produced instances. And only instances of categories are countable.)