It is an astonishing fact that there are laws of nature, rules that summarize conveniently (1)_____ qualitatively but quantitatively-how the world works. We might (2)_____ a universe in which there are no such laws, in which the 1080 elementary particles that (3)_____ a universe like our own behave with utter and uncompromising abandon. To understand such a universe we would need a brain (4)_____ as massive as the universe. It seems (5)_____ that such a universe could have life and intelligence, because being and brains (6)_____ some degree of internal stability and order. But (7)_____ in a much more random universe there were such beings with an intelligence much (8)_____ than our own, there could not be much knowledge, passion or joy. (9)_____ for us, we live in a universe that has at least important parts that are knowable. Our common-sense experience and our evolutionary history have (10)_____ us to understand something of the workaday world. When we go into other realms, however, common sense and ordinary intuition (11)_____ highly unreliable guides. It is stunning that as we go close to the speed of light our mass (12)_____ indefinitely, we shrink toward zero thickness (13)_____ the direction of motion, and time for us comes as near to stopping as we would like. Many people think that this is silly, and every week (14)_____ I get a letter from someone who complains to me about it. But it is virtually certain consequence not just of experiment but also of Albert Einstein's (15)_____ analysis of space and time called the Special Theory of Relativity. It does not matter that these effects seem unreasonable to us. We are not (16)_____ the habit of traveling close to the speed of light. The testimony of our common sense is suspect at high velocities. The idea that the world places restrictions on (17)_____ humans might do is frustrating. Why shouldn't we be able to have intermediate rotational positions? Why can't we (18)_____ faster than the speed of light? But (19)_____ we can tell, this is the way the universe is constructed. Such prohibitions not only (20)_____ us toward a little humility they also make the world more knowable.