Why we think we can comprehend everything

Humans think they can comprehend everything well because we have so far in everything that we are still searching for or are we? Apparently it seems that for every matter in which we begin to question our selves about a specific phenomenon or action or reaction we seem to come up with a solution or explanation in the most scientific and understandable way. Thats why as humans we differ so much from animals and that we learn from everything around us. As quoted from the great Einstein "The most in-comprehend-ably scary thing in the universe is that everything is comprehend-able". This statement cannot not be more true as everyday more and more things are understood on a multitude of levels.