Being and Time mentioned in "Being and Time", has been identified by some with Heidegger's central notion of "Sorge" ("cura", care or concern). However, for Heidegger, "theoretical" knowledge represents only one kind of intentional behaviour, and he asserts that it is grounded in more fundamental modes of behaviour and forms of practical engagement with the surrounding world. Whereas a theoretical understanding of things grasps them according to "presence," for example, this may conceal that our first experience of a being may be in terms of its being "ready-to-hand." Thus, for instance, when someone reaches for a tool such as a hammer, their understanding
Being work of such influential theorists as W. V. O. Quine, to name one of many. One of the most fundamental questions that continues to exercise philosophers is posed by William James: "How comes the world to be here at all instead of the nonentity which might be imagined in its place? ... from nothing to being there is no logical bridge." The deficit of such a bridge was first encountered in history by the Pre-Socratic philosophers during the process of evolving a classification of all beings (noun). Aristotle, who wrote after the Pre-Socratics, applies the term category (perhaps not originally)