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
Philosopher in Meditation and titling it "Philosopher in Contemplation" or "Philosopher with an Open Book". Yet the real credit for the attribution to Koninck should go to John C. Van Dyke, who wrote: "In fact, one may be heretical enough to think that someone like Koninck or Dou may have painted them..." The subject matter and details of the Koninck picture seem to have been directly inspired by a Rembrandt etching dated 1642 and representing "St. Jerome in a dark chamber" (Bartsch 105), which is the only other known work by Rembrandt that features a complete helical staircase. The traditional iconography of the