The paper focuses on Reinhardt Grossmann’s analysis of the Argument from Physics, as well as the analysis by the Spanish philosopher Antonio Millán-Puelles, in an attempt to assess the validity of the Argument on the basis of their respective critical views. Both authors agree in perceptual realism and in the need to distinguish between the scope and objects of Physics and the ordinary objects of natural perception. Their criticisms mainly concern the inappropriate use of the principle of reduction in the Argument and the distinction between secondary and primary qualities, which is, according to Grossmann, one of the sources of idealism and phenomenalism.