One of the most amazing things that every human does (in fact every animal with eyes (probably)) is figure out how to see.
Now I can’t remember the time before I learned to see – or rather before I learnt to make any sense out of what I saw – but I’m reasonably certain that we’re not born with the idea of 3-dimensional space. The effect the game of peek-a-boo has on babies is evidence of this. If the child had a sense of 3-d space as developed as that of an adult it would not be fooled into thinking that an object had disappeared because it was covered by another object. This indicates a progressive creation of the concept of space.
Think about what it actually is that you see. You don’t see 3 dimensional objects. What you see are a load of 2 dimensional shapes. As you move these shapes undergo geometric transformations such as reflection, stretching, increase/decrease in size and change of shape. We make sense of all these transformations through the concept of 3 dimensional space. In effect what we see (the 2-dimensional image) is a representation of reality (which may or may not be 3-d) and what we experience is a 3 dimensional represention of a 2 dimensional representation of reality (or something).
Imagine yourself in the position of the baby before it has even created this concept. What evidence/information does it have to go on? We wouldn’t be able to conceive of such things as are represented by the sentence “When I move my neck the shapes undergo so and so transformation.” Rather we would be limited to saying things like “When I have a certain sensation then the shapes I see undergo so and so transformation”. This is because the concept “moving my neck” presupposes the concept of 3-d space.
The amazing thing is that out of this famine of information babies create the concept 3-dimensional space that makes sense of so many disparate elements. Not only visual elements but it brings into one cohesive whole touch, smell, taste, sight and hearing. I mean think about; it’s awesome! It makes what Einstein did seem paltry.
A similar puzzle is how does a baby learn language?