<p>We consider the Bianchi type-I model of the universe in the Wheeler-DeWitt quantization scheme with the matter degree of freedom represented by a scalar field. As a consequence, the quantum mechanical equation of the universe is obtained in the minisuperspace consisting of the Misner variables and the scalar field. Employing Dirac factorization, we find that the logarithmic volume parameter makes a legitimate choice for the clock variable, consistent with Teitelboim’s analysis. On the other hand, the matter clock leads to inconsistencies with various quantum mechanical criteria. We further find that the minisuperspace orbital angular momentum operator does not commute with the Hamiltonian of the Dirac-type equation. The missing part of the angular momentum turns out to be the Pauli spin operator, whereby the total angular momentum becomes a constant of motion, consistent with the fact that the universe is a closed system. The emergence of the spin operator is owing to the inherent anisotropy in the Bianchi type-I model.</p>