Well, the thought that leaps to my mind is that smell isn&#x27;t like most of the rest of the senses. Eyes and ears are so easy to quantify and abstract with quantities that we&#x27;ve been doing it for decades now. Even if our eyes are not literally CCDs and our ears are not literally microphones, they&#x27;re close enough for the quantifications to be useful. Touch and proprioception back to a geometric shape (our body) which provides obvious spatial abstractions (higher, lower, harder, softer, etc). Taste (considered separately from smell, which is normally a bad idea but bear with me here) is based on a small number of types of sensors (sweet&#x2F;salt&#x2F;sour&#x2F;bitter&#x2F;umami, if there&#x27;s one or two missing it doesn&#x27;t change things much).<p>Smell is hundreds or thousands of distinct sensor types for various chemical characteristics, with no <i>particular</i> relationship to each other. We don&#x27;t have a systematic coverage of some vector space of X dimensions, we have quasi-random point samplings that poorly populate an n-dimensional space. If it&#x27;s hard to get abstract concepts out of that, it could be because it really is mathematically demonstrably difficult to get useful abstraction out of that source of data. It sounds to me like even those cultures that happen to have them are still very, very weakly covered compared to vision or sound.