“Man as a measure for all things“

In order to survive, individual organisms have to ‘communicate’ with their exterior. To import nutrients and to export the by-products of their metabolism.
In order to thrive, individual organisms need to know as much as possible about what’s going on as far as possible.
In order to maintain their congruence – read sanity, individual organisms which happen to be aware of their own selves have to make sense of what’s going on around them.

We, the only fully conscious beings know to man – to us, gather information using what we call ‘senses’. In order to survive, thrive and make sense of the world we smell, taste, touch, listen to and look at it. At the world.
Smelling and tasting have very much in common with ‘feeding’. The organism ‘imports’ tiny bits from the surrounding reality and uses them to learn things about what’s going on around it.
Touching is the first sense which ‘closes’ the frontier between ‘inside’ and ‘outside’.
Hearing is about becoming aware of other things interacting among themselves. Hearing a stream flowing means water moving relative to the banks. Also, hearing means both the hearer’s ears and the interacting things reside inside the same sound transmitting medium.
Seeing means becoming aware of light bouncing off things happening to be ‘in range’. The seer’s ability to see depends on light being emitted in such a manner as to be reflected – or obscured – by the observed object towards the eyes of the seer.
Making sense of things means integrating gathered information into a scenario where no piece of information contradicts any other. Specially any byte of information stored in the long term memory and held to be true.