There are four main interfaces with observable phenomena.
1. Action based on skeletal motion involves neurons controlling muscles that in turn control joint rotations.
2. Vision through the eyes produces a pixellated image sent through the optic nerve.
3. Simple observable behaviours, based on both action and vision, involve coordinated movements by single individuals over a limited stretch of time. More complex behaviours involve coordinated and cooperative actions of social groups over more extended time periods.
4. DNA, and the hope of eventually being able to decode the embedded information, is the fourth interface. Even though we cannot yet 'read' DNA, it provides important constraints, since innate skills leading to instinctive actions must have been encoded in the DNA.