Although life and questions connected with its definition among traditional philosophical topics, at the beginning of the twenty-first century and after roughly two and a half thousand years of philosophical tradition no satisfactory definition of life is at one’s disposal. Though difficulties bond up with life definition don´t accompany philosophy alone, but also almost all fields touched by this topic. Causes of this state of affairs can be viewed as a combination of several complementary connected facts. Those facts are in (...) the text stated as reasons against the possibility of creating universal definition of life and apply here one by one to the origin of life a postulated boarder line between life and nonlife, evolution of life and its variedness, multiplicity of definitions of life and still going discoveries of new organisms, philosophical tradition and lack of clarity of concepts, evolution of life as a historical process, critique of definitions of life from the point of view of „sample one“ and reflection of the concept life by conceptual analysis. Particular sources are about to be analyzed from the point of philosophy of biology with care for philosophical tradition, to questions linked with life and its selected definitions, to actual findings and explorations focused on life and possible contribution of philosophy to the endeavor of finding definition of life as such. Ground of proposed text is naturalism, physicalism and reductionism. (shrink)

In Zettel, Wittgenstein considered a modified version of Cantor’s diagonal argument. According to Wittgenstein, Cantor’s number, different with other numbers, is defined based on a countable set. If Cantor’s number belongs to the countable set, the definition of Cantor’s number become incomplete. Therefore, Cantor’s number is not a number at all in this context. We can see some examples in the form of recursive functions. The definition "f(a)=f(a)" can not decide anything about the value of f(a). The definiton is (...) incomplete. The definition of "f(a)=1+f(a)" can not decide anything about the value of f(a) too. The definiton is incomplete.<br><br>According to Wittgenstein, the contradiction, in Cantor's proof, originates from the hidden presumption that the definition of Cantor’s number is complete. The contradiction shows that the definition of Cantor’s number is incomplete. <br><br>According to Wittgenstein’s analysis, Cantor’s diagonal argument is invalid. But different with Intuitionistic analysis, Wittgenstein did not reject other parts of classical mathematics. Wittgenstein did not reject definitions using self-reference, but showed that this kind of definitions is incomplete.<br><br>Based on Thomson’s diagonal lemma, there is a close relation between a majority of paradoxes and Cantor’s diagonal argument. Therefore, Wittgenstein’s analysis on Cantor’s diagonal argument can be applied to provide a unified solution to paradoxes. (shrink)