lapalissade
An obvious, self-evident truth, especially humorously so; a tautology or truism.
In a certain way our theory is so obvious that it appears to us as a “lapalissade”. The cell is a network of phospholipid membranes and one of their chief functions is to keep certain substrates and enzymes apart.
Where it comes from
From French lapalissade, equivalent to Jacques de la Palice (a French nobleman and military officer) + -ade; see Lapalissian for more.
Adapted from the Wiktionary entry lapalissade (CC BY-SA 4.0).