For Heidegger, nothing is a thing, and a very important one at that. It sometimes enjoys the honour of taking a definite article, the nothing; and it even does things: nothing nihilates (1977b: 105). This will strike many contemporary philosophers as a simple confusion. In modern logic, nothing’ is a quantifier phrase. not a noun phrase. Nothing is not there fore a substantive. Heidegger was criticized on just this point in a very famous attack by Camap. Referring to What is Metaphysics?’, Carnap saysFrom "Heidegger and the Grammar of Being".
The construction of sentence (I) [‘We seek the Nothing’] is simply based on the mistake of employing the word ‘nothing’ as a noun, because it is customary in ordinary language to use it in this form in order to construct a negative existential statement . . . . In a correct language, on the other hand, it is not a particular name, but a certain logical form of the sentence that serves this purpose.But Heidegger is not confused. He is well aware that ‘nothing’ may be a quantifier. It may also function, however, as a perfectly legitimate noun phrase. For example, in his essay ‘The Metaphysical Foundations of Logic’, he says
‘Thinking about nothing’ is ambiguous. First of all, it can mean ‘not to think.’ But logic as the science of thinking obviously never deals with not thinking. Secondly, it can mean ‘to think nothingness’, which nonetheless means to think ‘something’. In thinking of nothingness, or in the endeavour to think ‘it’, I am thoughtfully related to nothingness, and this is what thinking is about.And Heidegger is right about this. ‘Nothing’ can be used as a substantive. If this is not clear, merely ponder the sentence ‘Heidegger and Hegel both talked about nothing, but they made different claims about it’. ‘Nothing’ cannot be a quantifier here.