It seems natural to think of truth as something absolute and 'out there' in the world.
Indeed, I find within me when I choose to contemplate it, the very idea that truth might not be absolute raises a flurry of indignation. The serious contemplation that truth might not be external feels threatening to our existential security. There does, after all, have to be an 'outside' world and there must be 'facts' about it which are true. Descartes, of course, noticed that he could doubt this without logical error but I doubt that he entertained the possibility for long that the world outside our minds is a pure fiction. There are other possibilities of course: Your mind could exist in a sophisticated computer simulation of many different types. Perhaps your entire mind is a computer with no biological components, and the very idea of a biological being is just part of the simulation. Or perhaps you could be wired up as a biological being, matrix style, with just your experience simulated. I say you here because perhaps there is only you in the simulation, but it could also be 'us' that are in a shared simulation – all of humanity, or even just the bits of it that you have met. There is even a well formed argument complete with all of the appropriate calculations to say that it is more likely that you are part of a complex simulation run by an alien intelligence than it is that the world is 'real' in the ordinary sense. This is because the universe is large and could be full of near infinite 'alien' civilisations running near infinite simulations just for fun. The term 'near infinite' is of course nonsense if you think of it in the sense that a huge number might be near infinity. Any arbitrarily vast number is, of course, infinitely distant to infinity. 'Near infinity' would simply be a bad usage if it wasn't for the fact that the nearness of numbers to each other is a metaphor. A spatial one. The distance between numbers can not be measured in millimetres or miles so they don't really have the property of 'nearness' which is a spatial thing. Instead they have a concept of ordinality that borrows the spatial metaphor of near or far. This metaphoric nature gives us some wiggle room to say that the nearness of numbers is in the mind's imagining. I can imagine a vast but finite number and it appears close to my limited and flawed imagining of infinity. This is enough to give the expression 'near infinite' its effortless meaning – the one you understood immediately and before the pedant or critic or stickler for correctness in you said “wait a minute – near infinity?”.
In any case, let's return to discussions of the truth. Gurus of all kinds have been saying for millennia that 'Maya' or 'Samsara' - the world, is an illusion. Perhaps they know something? So, contemplating that truth might not be absolute tends to spin us off into 'nothing is real' or 'the world is an illusion' type of territory. Indeed, much of the thinking in this area, in phenomenology for example, has been curiously silent about what the world is if it is not what we think it is.
We will get to some rigour in a moment but I want to introduce the idea that there is a more interesting and fundamental way to understand truth. One which shows its limitations and strengths and one which leaves us still some solid ground once we're done.
We exist as biological beings with wet neural networks for navigating our survival in the world, and however 'true' a fact in the outside world is, each individual of us can only asses and hold that truth as a structured process within a mind. We are accustomed to this idea under the guise of 'knowing'.
In a sense it seems as though we have come in a circle back to the beginning. That we can have various complex, messy and imperfect ways of knowing or not knowing is not new and the whole situation is modelled in the notion of 'knowing the truth'. We have various ways of knowing 'pure' existent truths, is the standard model and has been a cornerstone of western thought at least since Socrates. I would like to argue that this very idea is a mismodelling.
Before we go on to understand why this idea of truth is mismodelled we had better understand the idea of mismodelling. It is, after all, going to become central to much of the thinking done here. To understand it we need to back up a bit...