What is UDASSA?UDASSA is a philosophical "theory of everything" (TOE). It provides a framework to understand the universe and our place within it.
That sounds very mystical!No, UDASSA is not mystical, although it is arguably metaphysical. It is, instead, grounded in mathematics, physics and philosophy. It provides an in-principle mathematical approach to answer fundamental questions like, is the universe I see around me real or just a figment of my imagination?
So, which is it?Which is what?
Is the universe real or just a figment?Unfortunately, although UDASSA provides a framework and methodology to answer this kind of question, actually working out the answer would require more computing power than exists today, in fact more than we may ever have practical access to. Nevertheless I think it is a step forward to provide a methodology to answer this kind of question, even if it may never be able to be applied to get a practical answer.
What other kinds of questions can UDASSA answer?UDASSA aims at questions relating to our conscious perception of the universe. It can address issues similar to the one just mentioned, like, are we in "the Matrix", i.e. is what we experience just a computer simulation run by someone? It can discuss whether other "parallel" universes exist. It gives a probabilistic answer to the question of whether there are likely to be other intelligent life forms in our own universe. It explains why the universe is as big as it is, and why the universe is structured and lawful rather than chaotic or static. It gives a methodology that can in principle discover the exact laws of physics, and in fact it predicts that that there is no one set of laws that works, but rather a wide range of possible laws, which exist in a sort of mixture.
UDASSA also addresses issues from the philosophical literature relating to conscious experience. One of the big questions there is what counts as an implementation of a given computation, such as a hypothetical conscious computer programs? Some philosophers have argued that this must be answered very broadly, even to the point where every system can be seen as implementing every program. UDASSA refutes this point in a quantitative manner and allows numerical computation of the degree to which a given system implements a program.
What other theories and philosophies is UDASSA related to?UDASSA is based most directly on the work of Juergen Schmidhuber, a computer scientist who studies certain theoretical aspects of Artificial Intelligence. It is also influenced by the multiverse models of physicist Max Tegmark, who recently co-authored a Scientific American article describing his theory. The main ideas were pioneered by computer security expert Wei Dai, who discussed the basic concepts on his "everything exists" Internet mailing list during the 1990s.
Why is it called UDASSA?UDASSA is short for UD+ASSA, a description of the two parts of the model. UD is the Universal Distribution, a probability distribution over information patterns used in decision theory and other parts of mathematics. ASSA is the Absolute Self-Selection Assumption, a variant on an idea by Nick Bostrom which basically says that we should reason as if we are random or average observers from among all who exist. Putting these two parts together we achieve a mathematical and philosophical framework describing everything that exists, and how conscious entities perceive and interact with the universe.
How can we learn more?Follow this link to the Summary of UDASSA, or here for the History of the UDASSA concept.