PSIM describes what Sellars sees as the major problem confronting philosophy today.  This is the “clash” between “the ‘manifest’ image of man-in-the-world” and “the scientific image.” These two ‘images’ are idealizations of distinct conceptual frameworks in terms of which humans conceive of the world and their place in it.  Sellars characterizes the manifest image as “the framework in terms of which man came to be aware of himself as man-in-the-world” (PSIM, in SPR: 6; in ISR: 374), but it is, more broadly, the framework in terms of which we ordinarily observe and explain our world.  The fundamental objects of the manifest image are persons and things, with emphasis on persons, which puts normativity and reason at center stage.  According to the manifest image, people think and they do things for reasons, and both of these “can occur only within a framework of conceptual thinking in terms of which [they] can be criticized, supported, refuted, in short, evaluated” (PSIM, in SPR: 6; in ISR: 374).  In the manifest image persons are very different from mere things; things do not act rationally, in accordance with normative rules, but only in accord with laws or perhaps habits. How and why normative concepts and assessments apply to things is an important and contentious question within the framework. 