They want to program a system with a bunch of general knowledge and the ability to model the world, and they are coming up against the fact that some of what happens is stuff that the computer does and that will give rise to the possibility of paradox. The people that have unavoidably encountered it are people who are trying to program an artificial general intelligence (an AGI). This is something that we can ignore in some contexts. Any system that is modelling the universe as a whole – aiming for full coverage of all of existence – is going to encounter self-reference.

And that means that however we regiment the universe, whatever regime we work in, if we aim for a theory that describes all of existence, self-reference is unavoidable.

Ultimately, though, we are part of the universe. We adopt, that is to say, the God’s Eye View. And even though cosmology is explicitly devoted to the study of the universe as a whole, it is customary in cosmology to maintain the imaginative fiction that we – the people modelling the universe - are looking at it from the outside. We maintain a separation of subject and object, or of investigator and system being investigated.

Most day-to-day physics is modelling other systems: cells, gases, planets. This isn’t something that one often confronts in physics. Doing so can help make sense of the passing of time and our experience of free will, writes Jenann Ismael.Īny attempt to describe the universe as a totality inevitably involves self-reference. Rather than imagining that we are somehow outside of the universe that physicists model, they should see our embedded intelligence as a central part of reality and as critical to what happens.

Another word for running interference