The imaginary-time formulation is a useful extension of continuous real time in various branches of SR, GR, and QM, but there are deep uncertainties as to the physical meaning of what is involved. Of course, QM itself suggests that the universe might not be explicable in every sense of the word, but we should certainly worry about the operational meaning of imaginary time. If the only way the early universe could be understood is in terms of what amounts to a ‘black box’ approach, then the objective of obtaining a fundamental theory seems to have been defeated. Imaginary time touches on deep issues involving thermodynamics and the relationship of mixed states versus pure states in QM. If the view is taken that the only thing of physical significance is the irreversible acquisition of information, which is in fact the only thing laboratory physics can deal with, then physics should be described by asymmetric process time rather than the symmetric manifold time of a geometric, Block Universe. Imaginary time lacks any asymmetry or arrow of time, which is the perhaps the real cause for concern.