Can Gravity be Quantized?

Since the advent of general relativity and quantum mechanics their unification has been the ultimate goal of theoretical physics. So far, however, the different approaches aimed at creating a theory of quantum gravity [1] have been unsuccessful. It seems a possible reason for this – that gravity might not be an interaction – has never been consistently examined. What also warrants such an examination is that an experimental fact – falling bodies do not resist their apparent acceleration – turns out to be crucial for determining the true nature of gravitational phenomena, but has been effectively neglected so far. Taking it into account, however, makes it possible to refine not only the quantum gravity research (by recognizing that the genuine open question in gravitational physics is how matter determines the geometry of spacetime, not how to quantize what has the appearance of gravitational interaction) but also to fine-tune the search for gravitational waves by showing that astrophysical bodies, modelled by point masses whose worldlines are geodesics (representing inertial or energy-loss-free motion), do not give rise to radiation of gravitational energy. As too much is at stake in terms of both the number of physicists working on quantum gravity and on detection of gravitational waves, and the funds being invested in these worldwide efforts, even the heretical option of not taking gravity for granted should be thoroughly analyzed. It should be specifically stressed, however, that such an analysis will certainly require extra effort from relativists who are more accustomed to solving technical problems than to examining the physical foundation of general relativity which may involve no calculations. Such an analysis is well worth the effort since it ensures that what is calculated is indeed in the proper framework of general relativity and is not smuggled into it to twist it until it yields some features that resemble gravitational interaction. The standard interpretation of general relativity takes it as virtually unquestionable that gravitational phenomena result from gravitational interaction. However, the status of gravitational interaction in general relativity is far from self-evident and its clarification needs a careful analysis of both the mathematical formalism and the logical structure of the theory and the existing experimental evidence.