  Reinach notes in his Marburg lecture (1914) that, while many philosophers had acknowledged the existence of a priori truths, most had restricted the a priori to a very narrow sphere, confining it either to the formal a priori (Hume) or to the a priori of Newtonian physics (Kant). For Reinach, in contrast, there are material a priori structures in every domain of reality. If we know that only a free agent can be responsible, then this is because we understand the necessary and timeless natures of freedom and responsibility. In “Concerning Phenomenology” Reinach states that “the realm of the a priori is incalculably large … [and this] opens up for investigation an area so large and rich that still today we cannot see its boundaries” (1914, pp. 215–216). In defending the existence of material a priori truths (also called ‘essential laws’), Reinach and his colleagues thus believed that they had established a new kind of research agenda for philosophy. And while in many respects this is an agenda which combats reductionism, its proponents have at the same time provided us with several examples in which careful analysis of essences in the spirit of this agenda precisely refutes the existence of certain supposed entities.