 Finally, it is worth mentioning that Wittgenstein’s main contribution to the philosophy of music is probably something he almost never relates to music. This is the concept of aspect perception, exemplified by Joseph Jastrow’s famous duck-rabbit ambiguous figure, but also replicable in the auditory domain—e.g., hearing the metronome’s ticking as groupings of two or three. Contemporary philosophers of music have appealed in various ways to aspect perception, to shed light on issues that range from musical understanding to the phenomenology of musical expressiveness (see for instance Kivy 1989 and Arbo 2009; Guter 2020 observes that Wittgenstein’s interest in aspect perception was likely spurred by empirical studies on musical rhythm he made as a student).