Suppose in a double slit experiment, we place a machine that traps the gravitons emitted by the electrons and hence gives us the exact trajectory of the electrons(this would have no effect on the experiment as gravitons are liberated in any double slit experiment, just that we are able to measure it this time. This won't disturbing the system).At the same time, we find the velocity using our normal measurement using photons. Won't this violate the uncertainty principle?? The Godel's theorem suggests that we can never get a complete and consistent theory of all the force together. The above experiment(if it works!) suggests that gravity would not follow quantum mechanics. If Godel's theorem is correct for this, it means there has to be some discrepancy in the adding the four forces together, something like above.