Richard Dawkins has talked about this phenomenon. He says we live in a "middle world" and make all of our important judgments based on our size. (He says that our view of the universe would be fundamentally different if we lived on a different scale.)

http://www.ted.com/talks/richard_dawkins_on_our_queer_univer...

Because humans can only observe the universe from Earth's point of view, our perception is that we are in the middle of the cosmos. Yet we are only in the middle of what we can observe from our point of view at any angle. As you said, we can only observe so far in either direction or any direction as it were.

We're not really in the middle considering this scale goes from 10E-35m to 10E26m and we're in the 10E0 range. Looks like Pollen Grain and Silt are in the middle. OTOH, if you got rid of the ridiculous levels below the neutrino we'd be closer to the middle logarithmically.