The importance of the observer in science
  The concept of {\em complexity} (as a quantity) has been plagued by numerous contradictory and confusing definitions. By explicitly recognising a role for the observer of a system, an observer that attaches meaning to data about the system, these contradictions can be resolved, and the numerous complexity measures that have been proposed can be seen as cases where different observers are relevant, and/or being proxy measures that loosely scale with complexity, but are easy to compute from the available data. Much of the epistemic confusion in the subject can be squarely placed at science's tradition of removing the observer from the description in order to guarantee {\em objectivity}. Explicitly acknowledging the role of the observer helps untangle other confused subject areas. {\em Emergence} is a topic about which much ink has been spilt, but it can be understand easily as an irreducibility between description space and meaning space. Quantum Mechanics can also be understood as a theory of observation. The success in explaining quantum mechanics, leads one to conjecture that all of physics may be reducible to properties of the observer. And indeed, what are the necessary (as opposed to contingent) properties of an observer? This requires a full theory of consciousness, from which we are a long way from obtaining. However where progress does appear to have been made, e.g. Daniel Dennett's {\em Consciousness Explained}, a recurring theme of self-observation is a crucial ingredient. 
Russell K. Standish