  While there are close analogies between quantization in QM and in QFT there are also important differences. Whereas the commutation relations in QM refer to a quantum object with three degrees of freedom, so that one has a set of 15 equations, the commutation relations in QFT do in fact comprise an infinite number of equations, namely for each of the infinitely many space-time 4-tuples \((\mathbf{x},t)\) there is a new set of commutation relations. This infinite number of degrees of freedom embodies the field character of QFT.