Baskadia

It is clear that humans are conscious, while sticks and stones are not, and that animals are somewhere in between depending on whether they are primates or ants. The boundary of where consciousness starts is tricky for sure and depends on our definition of consciousness as much as on our ability to measure that consciousness.

A good place to start our discussion is human visual consciousness. Firstly, because it is so highly developed and is so very vivid to us. But also because we can experiment with it more easily than with say touch or taste. (But most importantly because that is what I researched in depth from 1979 to 1985).

I will structure the rest of the document as statements followed by justifications or explanations below it.

1. Our visual experience begins when light from the environment enters the eye and is focussed onto the retina. Rods and cones in the eye sense the light and transmit electrical impulses via the optic nerve to the brain.

An important aspect of the mechanics of the eye is that the retina is not covered uniformly with visual sensors like a modern camera is. The very central part of the retina, the Foveola is 250 μm wide, has a visual angle of just 1.2° and a cone density of 147,000/mm2 at its peak. However, in total the foveola has just 17,500 cones – ie colour sensors. The foveola is the central part of the fovea, and the fovea has approximately 200,000 cones and a visual angle of about 5°. The fovea and the foveola are critically important when we need the highest possible visual resolution, such as when reading a book.

This is in fact quite low resolution when compared with a modern camera. An 18 mega pixel camera has a pixel density of 1 million pixels per mm2 and has 18m pixels uniformly arranged, and a visual angle that can be very wide depending on the lens that is used.