Congratulations to Nicholas Danne who recently defended his thesis: Mathematical Realism from Reflectance Physicalism.
Danne also recently published "How to make reflectance a surface property" with Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics. For more of Danne's work see his PhilPapers.org page.
Do mirrors remain “reflective” objects in the dark, or does light shining onto a mirror instead give the mirror its reflective ability in the moment? More than an idle barstool question (like whether a tree falling in an abandoned forest makes a sound) the intrinsicality or light-independence of reflectance carries considerable philosophical import, since some philosophers reduce the human-visible colors to intrinsic surface reflectance. My dissertation, while remaining neutral on the best definition of color, argues that the received view of reflectance leaves it conceptually regressive and thus non-ascribable to surfaces. Rendering reflectance intrinsic to surfaces, I argue, requires a mathematized redefinition of reflectance, the literal interpretation of which implies a limited mathematical realism, itself a millennia-old philosophical bugbear. Without advocating mathematical realism per se, my thesis implicates a variety of current debates in scientific structural realism, metaphysical dispositional realism, mathematical nominalism, mathematical explanation, and even aesthetics, thanks to the philosophical precedent of reducing color to reflectance.
Here is the argument whose implications I explore throughout my dissertation chapters. The received view of reflectance defines it as the per-wavelength efficiency of a surface to reflect “pulses” of light, pulses being finite-duration propagations. I object that according to a well-documented law of nature, all electromagnetic pulses exhibit an inverse relationship between their duration and bandwidth, and that this relationship generates a vicious regress of the purported reflectance value at any wavelength. I block the regress by redefining “pulses” as superpositions of Fourier harmonics, which are infinite-duration monochromes. If harmonics reflect from surfaces, however, then they must be real.