Full context:   Whitehead also noticed that, in a sense, physicists are even more reductionist than Hume. In practice they rely on sense data, but in theory they abstract from most of the data of our five senses (sight, hearing, smell, taste, and touch) to focus on the colorless, soundless, odorless, and tasteless mathematical aspects of nature. Consequently, in a worldview inspired not by the actual practices of physicists, but by their theoretical speculations, nature—methodologically stripped from its ‘tertiary’ qualities (esthetical, ethical, and religious values)—is further reduced to the scientific world of ‘primary’ qualities (mathematical quantities and interconnections such as the amplitude, length, and frequency of mathematical waves), and this scientific world is bifurcated from the world of ‘secondary’ qualities (colors, sounds, smells, etc.). Moreover, the former world is supposed, ultimately, to fully explain the latter world (so that, for example, colors end up as being nothing more than electromagnetic wave-frequencies).