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 and Nothingness of metaphysics which denies or refuses grace inevitably ends by setting up in front of us the image of an atrophied and contradictory world where the better part of ourselves is finally unable to recognise itself." The philosopher Jean Wahl criticized Sartre's arguments about the topic of "nothing". The philosopher Frederick Copleston, writing in "A History of Philosophy" (1946–1986), described Sartre's view that all human actions are the result of free choice as "highly implausible", though he noted that Sartre had ways of defending his position. The British philosopher A.J. Ayer said that, apart from some psychological insights, the book