Being and Time raises the problem of "authenticity," that is, the potentiality or otherwise for mortal "Dasein" to exist "fully" enough that it might actually understand being. Heidegger is clear throughout the book that nothing makes certain that "Dasein" is capable of this understanding. Finally, this question of the authenticity of individual "Dasein" cannot be separated from the "historicality" of "Dasein". On the one hand, "Dasein", as mortal, is "stretched along" between birth and death, and thrown into its world, that is, thrown into its "possibilities", possibilities which "Dasein" is charged with the task of assuming. On the other hand, "Dasein's" access to
Apollonius of Tyre (philosopher) 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 one who wrote a work on female philosophers, or as the author of the