To search within the limits of the familiar and the sensible is to look for your lost keys under the lamp-post, ‘because that’s where the light shines’.
Tautology and Contradiction are the Logico-linguistic limits of the legitimate expression. They mark the boundary of the sensible. Go past that boundary and you are in absurdist territory.
Respectable folks largely live in the zone between Tautology and Contradiction, the mapped terrain of ‘Conventional Understanding’ [vyavharasatya].
Worthwhile Teaching however [and there is not much of it around], begins at this border and moves outward into zones of ever-increasing Absurdity.
The metaphor of the light under the lamp-post goes back to early Sufi literature but has been appropriated as the ‘Streetlight Effect’ by modern Academia.