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
Apollonius of Tyre (philosopher) chronological work () of which Stephanus of Byzantium quotes the fourth book, is uncertain. Apollonius of Tyre (philosopher) Apollonius of Tyre (; fl. 50 BC), was a Stoic philosopher. Strabo describes him as living "a little before my time," and says he wrote "a tabulated account of the philosophers of the school of Zeno and of their books," and which appears to have been a short survey of the philosophers and their writings from the time of Zeno. He is mentioned by Diogenes Laërtius as the author of a work on Zeno. Whether this Apollonius is the same as the