Merleau-Ponty's radical reflection conceptualizes the transcendental and the empirical as intertwined, emerging only via an écart. I advance this concept of transcendental empirical écart by studying the problem of measurement in science, in both general and quantum mechanical contexts. Section one analyses scientific problems of measurement, focusing on issues of temporality, to show how measurement entails a transcendental that diverges with the empirical. Section two briefly interprets this result via Merleau-Ponty's concept of depth, to indicate how measurement reveals a temporality that is not an already given ground that would guarantee the transcendental in advance: temporality is instead "deep,' itself engendering a divergence of transcendental and empirical operations that first allows for measurement and sense.