Work in philosophy on the individuation of the senses has often found touch to be a difficult case. This often has little to do with the physiological and functional diversity alluded to above. Even if we focus only on the phenomenological features of tactual perception, or on the typical objects of tactual awareness, touch seems to possess a diversity that resists any single unified account. Aristotle noted that touch, unlike the other dominant modalities, seemingly lacked a single “proper sensible” (for a recent empirical treatment, see Kung 2005).  On this account, a proper sensible is a sensory feature only available in a single modality, one that was constitutive of that modality (Marmodoro 2014). For vision color is the proper sensible. Any experience of color is visual, since no other modality provides awareness of that feature. The proper sensibles were contrasted with the common sensibles found in more than one modality. Touch doesn’t have a single plausible proper sensible. Instead it has multiple potential proper sensibles, including pressure and temperature. This too might be a strong reason for treating touch as a collection of distinct senses rather than a single modality.