As the SM and GR address two different but complementary aspects of reality and are not malleable into a single, unifying theory in any obvious or straight-forward manner, a constructive question is to ask why this should be so, or closer to the point: what is in the way of unification? On a very general level of analysis a possible answer could lie in the fact that the most basic and fundamental concepts of nature have not been grasped by thought or reasoning: nobody really knows what the true nature of space and time is; appendix A.7. Obviously any (or every) physical theory of the world intimately rests on this notion. Another deep concept concerns the realm of QM where man has `by accident' come across a new level of reality. As explained in appendix A.8 the problem here is not theoretical (i.e. mathematical) but conceptually related to the implications (and interpretations) of the quantum world, which also nobody fully understands. QM is the foundation of particle physics and could be said to be the underlying scientific theory on which modern civilization is based on. Its integration into GR as quantum gravity is also not fundamentally understood; appendix A.5. So, it may not come as such a surprise that any straight-forward attempt at the unification of all forces and matter (on the level of the SM and GR) fails. Thus a further understanding of reality is called for in order for unification to become manageable.
In the 13 century the philosopher and cleric Thomas von Aquin presented the Catholic church with a complete and absolute framework apparently reconciling and unifying all the philosophical and existentialistic enigmas of the time. Perhaps even more interesting than von Aquin's claim was the reaction of the church. Instead of stigmatizing him as a heretic, the Catholic thought system assimilated von Aquin's ideas, thus acknowledging the completeness of his weltanschauung; [Ec87]. A modern-day von Aquin faces a nearly insurmountable challenge. Not only would he need to understand all of science, he could also not universally express his belief, as there is no unified spiritual system of thought (Christianity, Buddhism, Hinduism and Islam accounting `only' for a large amount of followers not for a representative cross-section of all possible beliefs which also could include atheism, agnosticism, nihilism or naturalism). However, staring from a pragmatic positivistic point of view, one could conclude that spirituality (theology) is essentially a branch of science. Because if theology would become separated from science or contradict it then theology would surely loose its appeal for any rational person. Hence the situation is such that science covers and explains the physical reality we live in to an amazing extent. However, the problems science faces nowadays are extremely subtle and lie on the boarder-line to philosophy (and spirituality). The prominent questions are:
Returning to physics one can say that the beginning of the 21 century is a quite remarkable time in its development or evolution. From a level of obscurity and mystery, very clear and enlightening theories have been discovered. It appeared to many that it would not take long, before a single unified theory would emerge; e.g. Hawking's words cited in note . Unfortunately quite the opposite has happened. On the one side a single theory describing reality has indeed been found, but at a tremendous cost: not only has theory overtaken experiment, but also is the mathematical involvement so intense that no one can predict when the theory will be fully understood. On the other side the hitherto undisputed fundamental theories underlying GR and the SM have taken blows, as (ironically) the experiments in those areas get ever more sophisticated. Within the context of the SM see note , especially items 3 and 4. GR is also under intense surveillance as theoretical alternatives abound (note ) and our knowledge of the long-range dynamics is obviously not complete (chapter 3). Maybe even worse, the mathematical formalism on which physics (and science in general) is founded on also seems to display some very puzzling and bizarre properties. But what is really unsatisfactory about all of these challenging problems is how the science community is reacting to them. Firstly, the bulk of theoretical physicists is (understandably) preoccupied with string/M-theory, in effect leaving no time for a basic analysis of new facts, e.g. that there exists a `fifth force' in the universe and that photons can have group velocities greater than . This gives the experimental physicists the burden of not having sufficient theoretical support! So in essence most of these dazzling new findings are ignored by the main-stream. This unfortunately allows many potential (scientific and non-scientific) von Aquin's to co-exist at the same time, every one offering his personal view of how things should work. Perhaps the only constructive modus operandi is an eclectic one: from the myriad of consistent mathematical models with allowed phenomenology one must select those elements which can be viewed as basic truths of reality without inventing new concepts. Ideally these elements should appeal in a scientific and philosophical (even perhaps spiritual/mystical) way. The next step would be to weave these elements into a consistent tapestry. Also, one should not forget that maybe the answers to physics (especially the understanding of string/M-theory) can only arise within a greater context incorporating the phenomenon of life and consciousness. After all, physics is done by physicists who are living thinking entities (even if one doesn't accept the premise of anthropic principles; ). A proposed set of such `axioms' would be