Statements of fact in everyday life and in science are almost certainly in one of two categories: false or vague (lacking truth value). If a statement is supposed to represent a state of the world and is true if and only if that state actually obtains in the actual existing world then of course everything is going to be false or true by coincidence, we don't have access to the actual existing world. Such a requirement for truth, however, is stupid and completely useless. An alternative is that statements purport descriptions of models we have of the world. Models have an ontology: the things that exist in that model. Models have other features to tie those elements together such as forces, laws, rules, glue, and imaginings (depending on the model). Sophisticated models, like Newtonian physics, evolutionary biology, and our implicitly held folk models of social and physical behaviors, create a vast interconnected web of relations and dependencies; a well formulated fictional world. The most we can ever expect to mean by 'true' is true in a fictional world.

The first point is a Humean truism: since our "knowledge" of the world is delivered through our senses, all statements about the world must actually be about a fictional mental model based on data from our perceptions. Naïve realists make a pretty good case that the things we say about the world are really about the world and that insofar as I can knock this table this table really exists. Within a reductionist framework we can go even further than the Humean in denying the naïve realist position. Even granting that our perceptions are reliable revealers of a real world, my perception of a table object isn't a perception of an existing thing. This table is made of atoms; in fact we say it is constituted by atoms to underline the fact that there isn't both a table and a collection of atoms under my computer. If we are talking about interior design then we'll probably say that tables are existing things, but that's just the ontology for the furniture/room model. If we're talking about the real world's ontology then we can't double count the atoms and the table – the table does not exist in the real world if atoms do.

Complex systems theory is within a reductionist framework so we have secured that the set of objects that exist must all be at the same level of organization. Furthermore, we are used to thinking of objects as coherent behaviors of constituent parts; i.e. emergent phenomena. A statement about the body, (say) is actually a statement about aggregates of organs which is actually a statement about cells and all the way down. If feels strange to say that it is really true that unicorns are white because there aren't any unicorns "in the world". Whatever it means for a statement about a fictional object to be true it doesn't mean that it is instantiating in the real world. Now consider the statement "My body has two arms". My body doesn't really exist, it's just an aggregate of cells and aggregates of cells can't have arms. We make a conceptual leap from the aggregate of cells to the body, but the body doesn't exist as a physical object. Just like the unicorn exists in a model of mythical creatures and stories, the body exists in models of biology and most of the folk models that allow us to live our lives.

So a scientific claim is true if it is coherent with the model under consideration. That's all, that's what 'true' means. The models are fictional worlds; they posit objects and interactions that may have absolutely no bearing on reality. There may not even be a reality. It's irrelevant to the models and to whether the statements of the model (theorems or corollaries) are true…except claims in the model that the model corresponds to reality. Claims about matching reality are either nonsense (if there isn't a reality) or false (because reality can't actually be the way it is described in the models…tables (and people, and atoms, and hurricanes, and…) can't exist in the "real world". That's as far as I'll take this now, but there are lots and lots of implications of this result for the notions of causation, inference, mereology, emergence, machine learning, etc. It's a big result I guess, but it's pretty obvious too.