The cosmological primordial perturbations of the universe, implicitly defined by the Wheeler–DeWitt equation:

a partial differential equation determining a wave-function not defined in space or time or spacetime, with:

and satisfies an approximate Schrödinger equation:

are clearly quantum in origin. One of the central foundational philosophically pressing problems in physics is to describe a 'collapse' dynamics that explains the classical features consistent with astrophysical data. Given the 'no-time'-property of the Wheeler–DeWitt equation: namely, that it lacks an external time parameter and it lacks a first derivative with an imaginary Schrödinger time-factor, as well as its linearity and symmetrization, we face a deep conflict with the Lindblad equation:

given that its central properties are time-asymmetry and entanglement-entropic-irreversibility, and whose Lindbladian:

describes the non-unitary evolution of the density operator, with:

Besides the problem of the undefinability of the Lindbladian system-bath interaction:

and

in the quantum gravitational cosmology context: see Derivation of the Lindblad Equation for technical details, we already face the tripartite conflict of time