Nothing, no-thing, or no thing, is the complete absence of anything as the opposite of something and an antithesis of everything. The concept of nothing has been a matter of philosophical debate since at least the 5th century BC. Early Greek philosophers argued that it was impossible for nothing to exist. The atomists allowed nothing but only in the spaces between the invisibly small atoms. For them, all space was filled with atoms. Aristotle took the view that there exists matter and there exists space, a receptacle into which matter objects can be placed. This became the paradigm for classical scientists of the modern age like Newton. Nevertheless, some philosophers, like Descartes, continued to argue against the existence of empty space until the scientific discovery of a physical vacuum.

नास्तित्व या अनस्तित्व उस स्थिति को कहते हैं जिसमें कोई भी वस्तु उपस्थित न हो, अर्थात् अस्तित्व का पूर्ण आभाव हो।