A commentary on a conference paper of 1943 by Henry Margenau, this posthumously published text includes clarifications of the essences of and differences between (1) the eidetic and transcendental methods of Husserlian phenomenology and between (2) sense data, the properties of sensible objects, and the constructs produced in physics. Gurwitsch's emphatic endorsement of Margenau's methodology of physics is also quite significant.