Quantum physics provides a good candidate for a mathematical entity, namely, the quantum state vector in the Hilbert space. The causal potency problem originates from determinism: In classical physical theories there are fundamental constituents entering in the mathematical description of the physical laws that govern deterministically the dynamics of physical systems. Since only these fundamental constituents are causally potent to affect the deterministic behavior of physical systems, consciousness has to appear as a fundamental constituent of the physical theory as well. Existentialism clashes seriously with determinism. Classical deterministic physics allows no free will and no objective morality. Classically, functionalism leads to epiphenomenalism because the generated conscious experiences are unable to change the already predetermined future dynamics of the brain. In quantum physics, however, the quantum indeterminism in the dynamics of quantum systems provides a multitude of possible outcomes from the measurement process.