Chemical reactions and according to Roger Penrose this phenomenon begins to become expressed even at quantum scale. As I understand it, a quantum event is a threshold event. A limit has been exceeded and a corrective "action" takes place. While non-sentient particles cannot feel, they do in fact experience a "bing", a threshold event. An earthquake is experienced by all objects in its range of influence. They just don't know this, except for organic biology. It is what sets organics apart from inorganics, in the world of chemicals. But quantum is responsible for chemical action and reaction in both in-organic (elemental) chemicals and in organic (living) objects. IMO, Organic matter has evolved in acquiring a cognitive "sensitivity" to quantum events which translates quantum "bings" into sentient and emotional chemical reactions. This is the area Hameroff and Penrose are currently exploring. Micro tubules are tiny quantum computers.