In the penultimate line of the Tractatus, Wittgenstein famously declared the book itself to be nonsense. According to Graham Priest, this kind of self-referential contradiction is not peripheral, but rather central to philosophy when it reaches the limits of language. In this IAI interview, Oliver Adelson sat down with Graham Priest to discuss Wittgenstein, truth, paradox, and non-Western philosophy.

Oliver Adelson: Thank you very much for joining me, Graham Priest. You’ve written about various contradictions in philosophy and your own dialetheist approach to handling them. Could you give a brief overview of the sort of self-referential contradictions that you see running through the work of Kant, the early Wittgenstein, and other philosophers?

Graham Priest: There’s this phenomenon you get in philosophy from all the traditions I'm aware of – analytic, continental, east, west – where someone comes up with a view about the relationship between language and, for want of a better word, the world, such that there are things out there in the world that you can't talk about. They come up with a view to the effect that there are limits to language. There are many such views.

The problem that such a view faces is that, if you say there are such things, and even worse if you argue that there are such things – as all these philosophers do – then you must talk about them. So the view itself says that these things go beyond language. And yet, the very fact of arguing for it shows that they don't. That's the problem.

You find this view in many philosophers. One example is Immanuel Kant, who says that his view commits him to there being dinge an sich, things to which you can't apply the categories. But in talking about these things, you have to apply the categories. You get the problem in Wittgenstein, where he says that the very grammar of a correct language, an ideal language, is such that you can describe the world, but not the relationship between it and language – that can only be shown. But he does talk about it. A third example is Heidegger, who says that there is a difference between beings and what he calls Being, Sein – and Being is not an object, so you can't talk about it. And Heidegger is well aware of this problem – probably more than any other philosopher I know – and he struggles with the problem for decades. Just to finish and point out that this is not exclusive to Western philosophy: You get this in a number of Eastern traditions. In Mahayana Buddhism, it is pretty orthodox that ultimate reality is ineffable. And of course, all these guys talk about it. SUGGESTED VIEWING Nothing and everything With Graham Priest

I want to home in on the case of Wittgenstein. According to Wittgenstein's Tractatus, statements which have sense are those that picture states of affairs. But many of Wittgenstein's remarks in the Tractatus, as you hinted at, do not picture states of affairs according to his own account – even the first sentence of the work. What should we make of this contradiction?