1. Where The Eyes Are
1.1. My eyes lie a certain distance apart from each other. They can face different directions
My eyes are not exactly in the same spatial location. Not only are they not in the same spatial location, they do not always face in the same direction. One is much weaker and slightly squinted; when I am tired, it points a little inwards toward my nose. So,
- Each of my eyes is In a different place.
- At least sometimes, each of my eyes points in different directions. [Note 1]
‘1’ assumes eyes occupy a location in this space (this seems uncontroversial, and I’ll assume it). Further, that each can occupy a different location — again, uncontroversial and I’ll assume it. ‘2’ holds that my eye is pointing in a particular direction. But this is not as clear as ‘1’. It looks like a right thing to say. But: what gives an eye that direction? There are three possible answers:
A. An eye has an intrinsic direction.
It has a direction whatever else we define as having direction. If an eye is floating in an otherwise empty universe, it still points or faces in some way such that we can say: there is one whole heap of nothing in front of the eye and there is another whole heap of nothing behind the eye.
An eye’s direction of this kind is like the direction of an arrow or a signpost. There is a part of it that lies forward of the eye — analogous to the head of an arrow — and a part that lies back in the way — like the tail of an arrow. [Note 2]
B. An eye has an extrinsic direction.
Its direction is because of something else. It needs something else to say where it is pointing. If an eye is floating in an otherwise empty universe, it can’t be said to have anything lying in front or behind of it.
It is not like an arrow. It is like a line. We say what is at the front because of something else — something else which is like an arrow — and that something else gives it its direction. Draw an arrow and a straight line segment, and put the line segment in relation to the arrow in such a way that part of it is nearer the arrowtail than the ‘head, and part of it is nearer the arrowhead than the ‘tail. If asked ‘where is the segment’s front and back’, my bet is you’ll find it natural to have the front part near the arrowhead, the back part near the arrowtail. [Draw it. You’ll see what I mean].
C. A third possibility is that eyes have no direction, neither intrinsic nor extrinsic. But I am not sure what to do with that.
If ‘A’ and ‘B’ are right, then we can then also define spatial directions relative to the eyes. If an eye has a direction, we can talk about what lies along that direction, what lies to the left and right of that direction, what lies above and below that direction. But what defines that direction? What makes one thing, e.g., an apple I’m looking at, in front of the eye while making something else, e.g., the neural processing resulting from stimulation of the eye, behind the eye?