There has been much ado about nothingness amongst philosophers and mystics alike. Heidegger and Carnap famously argued fiercely about whether the ‘nothing nothings’ or whether this is meaningless, illogical, hogwash. Carnap though, in his later work, moved towards Heidegger’s perspective, and placed ‘the nothing’ beyond the clutches of logic. The ground of Being may well be a contradiction, argues Graham Priest.
Act I: Absences
In Being and Nothingness, Jean-Paul Sartre tells us a story.1 He has arranged to meet Pierre in a bar at 16.00. Pierre is always punctual. Jean-Paul arrives late. He enters the bar; Pierre is not there. At once Jean-Paul experiences his absence. He does not have to reason: ‘The things in the bar are: a table, a chair, Simone... Pierre is not a table; Pierre is not a chair; Pierre in not Simone;... Ergo Pierre is not in the bar.’ The absence of Pierre is immediate. He has a direct phenomenological awareness of an absence.
Or again: I visited my old family home immediately after the death of my mother. The place was exactly the same as it always was. But now there was nobody there. She was absent; and her absence was palpable.
Perhaps most of us have experienced this kind of absence. But the absences in question here are absences of particular things, Pierre and my mother. There is also an absolute absence: the absence of every thing: nothing(ness). Can one experience this?
Yes, according Martin Heidegger. His inaugural lecture at the University of Freiburg in 1929, discusses nothing(ness) at length, and he avers:2
Does such an attunement, in which man is brought before the nothing itself, occur in human existence?
This can and does occur, although rarely enough and only for a moment, in the mood of anxiety.
The first thing to note about this quotation is the unhappy translation. ‘The nothing’ barely makes sense in English. In German, when an abstract noun is used it is standard for it to come with the definite article (‘the’). This is not the case in English. The translation should simply be nothing, or maybe nothingness (to emphasize that this is being used as a noun-phrase—see below). The second thing to note is that what Heidegger means by ‘anxiety’ is not what the reader is first likely to think. It is not a feeling of anxiousness about some actual or possible event. It is a mood, an experience, which is directed at no thing in particular. Indeed all objects “slip away” and one is left with their ground—nothingness. Indeed, their “standing out” against this is what makes them objects:3
In the clear night of the nothing of anxiety the original openness of beings as such arises: they are beings—and not nothing. But this ‘and not nothing’ we add in our talk is not some kind of appended clarication. Rather it makes possible in advance the revelation of beings in general.
The similarity between Heidegger’s experience of anxiety and the Zen experience of satori has been noted by many.4
And just as the Eiffel Tower and Sherlock Holmes were phenomenologically present to you, so has nothingness been. It has been the object of your thought and, as such, experienced.
However, let us not pursue this train of thought. There are good reasons to suppose that nothing(ness) can be phenomenologically present in a much less exotic context. Think of the Eiffel Tower. (Done it?) The Eiffel Tower was phenomenologically present to you. (Of course, to think of the Tower and to experience the Tower (by seeing it) are quite different kinds of mental acts (noeses); but the Tower is the object of both of them.) Now think of Sherlock Holmes. (Done it?) This time, the object (noema) of your experience was Holmes. It makes no difference that Holmes does not exist. Intentional acts are often directed at things which do not, or may or may not, exist. Now think of nothing(ness). In fact, you have already been doing this for some time in reading this piece. You may have been wondering what, exactly, it is, or whether or not it exists. And just as the Eiffel Tower and Sherlock Holmes were phenomenologically present to you, so has nothingness been. It has been the object of your thought and, as such, experienced.
Act II: Grammar
Is this all confusion? So (at one time) argued Heidegger’s fellow countryman and contemporary Rudolf Carnap. In an article of his early logical positivist phase, in an explicit attack on Heidegger, he says:5
The construction of [the] sentence [‘We seek the Nothing’] is simply based on the mistake of employing the word ‘nothing’ as a noun, because in ordinary language it is customary to use it in this form in order to construct negative existential statements.
Carnap’s point is that the word ‘nothing’ is not a noun-phrase, but a quantifier. Quantifiers are terms like some, many, all, most. They do not refer. They simply record that some/many/all/most of a certain collection of things satisfy some condition or other. Hence to suppose that ‘nothing’ can refer to a thing which is the target of our seeking (literal or metaphorical), is just grammatical nonsense.
Carnap, acute thinker though he was, slipped up here. ‘Nothing’ can indeed be a quantifier term. If I say ‘Jenny was hungry. She went to the fridge but was disappointed. There was nothing in there’. The nothing in the last sentence is a quantifier. The sentence means: there was no thing (at least of an edible kind) that was in the fridge. As logicians would write it:
- ¬∃x(x is in the fridge and x is edible)
But ‘nothing’ is ambiguous. It can also be a noun phrase. When some Christian and Muslim theologians claimed that God created the world out of nothing, they did not mean that there was no x such that God created the world out of x. That would be true if God did not create the world at all. They meant: first there was nothingness (apart from perhaps God), and then... there it was. Or one may truly say:
- Hegel and Heidegger wrote about nothing, but said rather different things about it.
The it here is an anaphoric pronoun which refers back to whatever nothing refers to. So it refers.
Nor was Heidegger confused about the matter: he was well aware of the ambiguity. As he says (in his own inimitable style) in a series of lectures on the nature of logic given in 1928:6
‘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.
Indeed, a few years later, Carnap appears to have realised his mistake. In Meaning and Necessity, he writes:7
It is possible ... to count among the things also the null thing ... characterised as that thing which is part of every thing. Let us take ‘a0’ as the name for the null thing ... ‘a0’ seems a natural and convenient choice as descriptum for those descriptions which do not satisfy the uniqueness condition.
Ironically, Carnap himself was criticised by Peter Geach for advocating an object that ‘exists nowhere and nowhen’8—a strange thing for a Catholic to say, given that many theologians have argued that God exists outside of space and time.
Act III: Contradiction
In his critique of Heidegger, Carnap has another (less frequently commented upon) bone of contention to pick concerning talking about nothing(ness). This goes as follows:9
Likewise [the] sentence [‘The Nothing exists only because...’, Es gibt das Nichts nur, weil...] must be rejected for two reasons. In respect of the error of using the word “nothing” as a noun, it is like the previous sentences. But in addition it involves a contradiction. For even if it were admissible to introduce “nothing” as a name or description of an entity, still the existence of this entity would be denied in its very definition, whereas [the sentence] goes on to affirm its existence. This sentence, therefore, would be contradictory, hence absurd, even if it were not already meaningless.
One might demur from Carnap’s taking ‘es gibt ’ to impute existence; but the point that nothing(ness) is a contradictory object is right enough. By definition, it is not some thing. As Heidegger puts it in his inaugural lecture:10
[T]he nothing is the complete negation of the totality of beings.
Or to put it more bluntly: nothing is the absence of every thing, every object. It is what remains, as it were, when all objects are removed. So it is no object, no thing. Yet it is: one can think about it, talk about it (we have been). It is the object of various intentional states. So it is an object, some thing. Nothing (noun phrase) both is and is not some thing.
Carnap’s point was not news to Heidegger. He says in his inaugural lecture:11
What is the nothing? Our very first approach to the question has something unusual about it. In our asking we posit the nothing in advance as something that ‘is’ such and such; we posit it as a being. But that is exactly what it is distinguished from. Interrogating the nothing—asking what, and how it, the nothing, is—turns what is interrogated into its opposite. The question deprives itself of its own object.
Accordingly, every answer to this question is impossible from the start. For it necessarily assumes the form: the nothing “is” this and that. With regard to the nothing question and answer alike are inherently absurd.
Unfortunately Heidegger does not tell us there how to address the problem.
Act IV: Tolerance
Nothing(ness) walks us into the valley of the shadow of contradiction. Famously, Aristotle argued that:14
[f]or the same thing to hold good and not hold good simultaneously of the same thing and in the same respect is impossible...
His arguments are poor, however, as most scholars now agree;13 but notwithstanding this, Aristotle set the view—the Principle of Non-Contradiction—into high orthodoxy in Western philosophy. However, logic has gone a long way since Aristotle. In particular, the 20th century has seen a spectacular growth of systems of mathematical logic which reject many of Aristotle’s claims about logic.
Carnap—one of the central figures in the development of modern logic—was well aware of this fact, and responds to it in his book Logical Syntax of Language of (1937), written in his conventionalist period, with his celebrated Principle of Tolerance:14
In the foregoing we have discussed several examples of negative requirements ... by which certain common forms of language—methods of expression and of inference—would be excluded. Our attitude to requirements of this kind is given a general formulation in the Principle of Tolerance: It is not our business to set up prohibitions, but to arrive at conventions.
Some of the prohibitions which have hitherto been suggested have been historically useful in that they have served to emphasize important differences and bring them to general notice. But such prohibitions can be replaced by a definitional differentiation. In many cases, this is brought about by the simultaneous investigation (analogous to that of Euclidean and non-Euclidean geometries) of language-forms of different kinds—for instance... a language admitting and one not admitting the Law of Excluded Middle.
In a paraconsistent logic, this principle fails, so a contradiction can hold in a situation but be quarantined as a “singularity”, not spreading to unrelated areas.
All of the systems of logic known to Carnap at the time enforced the Principle of Non-Contradiction. However, within 20 years of Carnap’s book the subject witnessed the development of logical systems that do not. Such systems are now called paraconsistent logics. In many systems of logic (including the one you are likely to meet if you take Logic 100, there is a principle of inference called Explosion. According to this, if a contradiction holds in a situation, so does everything. In a parconsistent logic, this principle fails, so a contradiction can hold in a situation but be quarantined as a “singularity”, not spreading to unrelated areas. This is not the place to go into such logics and their applications further.15 Suffice it to say here that such systems of logic give precise rules which admit contradictions being true, show how to control them, and permit us to operate meaningfully with them. These logics have been applied to handle many logical paradoxes, such as the liar paradox and the sorites paradox; and the “paradox of nothingness”—that nothing both is and is not some thing—falls happily into place here.
Given these matters, we can see that with his Principle of Tolerance, Carnap implicitly walked back his second critique of discourse about nothing. As he says:16
In logic, there are no morals. Everyone is at liberty to build up his own logic, i.e. his own form of language, as he wishes. All that is required of him is that, if he wishes to discuss it, he must state his methods clearly, and give syntactical rules instead of philosophical arguments.
What to make of Carnap’s view is still a topic of intense debate amongst contemporary philosophers of logic. And of course, he might well have complained that Heidegger should have spelled out the rules by which he was operating more clearly—though one might say exactly the same about many (most) great philosophers.
On the other side of matters: Heidegger knew very little—if anything—about modern logic, even though many of the events I have referred to happened
in his lifetime. What he would have said about them had he addressed them, I leave for Heidegger scholars to argue about. However, as a matter of fact, Heidegger did come to the view that nothing (and its close cousin, being) really were contradictory objects.17 As he says in his personal notes of 1936–1938, subsequently published as Beiträge zur Philosophie:18
Non-being as a mode of being: it is and yet is not. And likewise being: permeated with the ‘not’ and yet it is. Those who fancy themselves only too clever and immediately uncover a contradiction here, since indeed non-beings cannot ‘be’, are thinking in much too narrow way with their ‘non-contradiction’ as the measure of the essence of beings.
In other words, nothing, as the ground of all objects, is so different from mundane things that one should not expect logic to apply to it—logic, of course, being Aristotelian, since Heidegger knew no other. At the very least, then, Heidegger might well have welcomed the developments in the subject which informed Carnap’s later view.
Our two German philosophers would, I am sure, have failed to reach agreement about very many things; but perhaps they could have reached a rapprochment over something—namely nothing.
 Sartre, J.-P. (1943), L’Eˆtre et le N´eant: Essai d’Ontologie Ph´enom´enologique, Paris: Gallimard; translated by H. Barnes as Be- ing and Nothingness: An Essay on Phenomenological Ontology, New York, NY: Philosophical Library.
[2, 3, 10, 11, Heidegger, M. (1967), ‘Was ist Metaphysik?’, pp. 1-19 of Wegmarken, Frankfurt am Main: Vittorio Klostermann Verlag; translated by D. Krell as ‘What is Metaphysics’, pp. 93–110 of D. Krell (ed.), Martin Heidegger: Basic Writings, revised and expanded edn, London: Routledge, 1993.
 Priest, G. (2021), ‘Nothingness and the Ground of Reality: Heidegger and Nishida’, ch. 2 of S. Bernstein and T. Goldschmidt (eds.), Non- Being: New essays on the Metaphysics of Non-Existence, Oxford: Oxford University Press.
[5,9] Carnap, R. (1932), ‘Überwindung der Metaphysik durch Logische Anal- yse der Sprache’, Erkenntnis 2: 219–241; translated by A. Prior as ‘The Elimination of Metaphysics Through Logical Analysis of Language’, pp. 60–81 of A. Ayer (ed.), Logical Positivism, New York, NY: The Free Press.
 Heim, M. (tr.) (1992), The Metaphysical Foundations of Logic, Bloom- ington, IN: Indiana University Press.
 Carnap, R. (1947), Meaning and Necessity, Chicago, IL: University of Chicago Press.
 Geach, P. (1949), ‘On Rigour in Semantics’, Mind 58: 518–522.
 Kirwan, C. (trs.) (1993), Aristotle: Metaphysics, Books Γ, ∆, E, 2nd edition, Oxford: Oxford University Press.
 Priest, G. (2006), Doubt Truth to be a Liar, Oxford: Oxford University Press.
 Priest, G., Tanaka, K., and Weber, Z. (2022), ‘Paraconsistent Logic’, in E. Zalta (ed.), Stanford Encyclopedia of Philosophy, https://plato.stanford.edu/entries/logic-paraconsistent/
 Carnap, R. (1934), Logische Syntax der Sprache, Vienna: Springer; translated by A. Smeaton as The Logical Syntax of Language, London: Routledge, 1937.
 Casati, F. (2022), Heidegger and the Contradiction of Being: An Analytic Interpretation of the Later Heidegger, New York, NY: Routledge.
 Heidegger, M. (1989), Beitr¨age zur Philosophie (Vom Ereignis), Frank- furt am Main: Vittorio Klostermann Verlag; translated by R. Rojcewicz and D. Vallega-Neu as Contributions to Philosophy (Of the Event), Bloomington, IN: Indiana University Press.