It is well known that by employing the universal constants as conversion factors it is possible to express the other so-called “fundamental” dimensions, mass, and length, in time units. The General Conference on Weights and Measures has endorsed this approach, working toward a scheme in which time will be the only such operationally defined concept in the foundations of physics. Taking this time-only version seriously as the proper formulation of the subject immediately reveals a quantitative (at least in an order of magnitude sense) candidate for the connection between quantum reality and the “consciousness” of the observer required by the Copenhagen interpretation. It is the time constant of their brain, τ, the average time it takes to process one bit of information. This is the... smallest increment of space-time the brain can deal with, the smallest piece from which it can acquire a complete bit. For humans, it is of order 10−18 s or as a length 3 Å, the size of atoms, so anyone observing reality at the subatomic level must find their knowledge to be incomplete because they are looking at fractions of a bit. This insight has not been noticed previously, presumably because a personal parameter like τ can have no role in the objective logic of physics. It leads to one obvious conclusion, that the amount human physics can learn about reality must be constrained by the power of our brains, and one far less obvious one, that this constraint is the source of the inherent uncertainties of quantum mechanics.