The relation between us and our surroundings is paradoxical. On the one hand, we sometimes feel that we and the things around us are part of a seamless whole. Thus mystics speak of experiences in which they meld into the background. On the other hand, things often resist our efforts to assimilate them to our purposes. We then experience them as separate from us and sometimes even as alien. Indeed, some thinkers have claimed to be overcome by nausea in the face of a landscape's muteness and seeming utter disregard for them. These ontological postures involve epistemological stances. Some thinkers emphasize the immediate accessibility of things to us; they postulate that we are internally related to these things and thereby already have an at least implicit knowledge of them in advance of any empirical learning. In contrast, those thinkers who stress the separateness between us and things hold that we are only causally or otherwise externally related to them and must therefore build up our knowledge of these things from scratch.

Phenomenologists have found each of these positions one-sided. They suspect that each of them involves an imposition of preconceived ideas on to the relationship between selves and the world. They think that both rationalists and empiricists have ignored the testimony of immediate experience in favour of ideas that have other sources. In order to escape this dilemma, phenomenologists perform their famous epoché and put aside common-sense or science-based conceptions of reality.