 It may also be questioned whether all determinates of determinables can be systematically compared, as per Determinate similarity/comparability. It is unclear, for example, whether being pentagonal is more or less similar in respect of shape to being square or being sextagonal. It is also unclear whether all determinates of smell admit of systematic comparability (is the smell of pine more similar to the smell of rose or of violet?), though recent empirical work identifying the dimensions of “smell space” (see, e.g., Mamlouk &amp; Martinetz 2004) may reveal an underlying structure of the sort (appealing to hue, saturation, and brightness) that serves as an underlying basis for ordering determinate colors (which work might also serve as a basis for responding to Armstrong, above). The question of whether all determinables may be systematically ordered with respect to their determinables, either explicitly or implicitly, matters to whether determinate/determinable relations can be modeled in spatial terms along lines proposed by Funkhouser (2006)  (see §3.6.1).