BHS -> Mr. Stanbrough -> Physics -> About Science -> this page
You now know that both of these statements are false - but that the uncertainty and change inherent in scientific progress are actually a strength of science. What else has changed our world as much in the last 400 years as science?
Most practicing scientists will tell you that science has made, and continues to make real progress toward real understanding of nature - that every change and adjustment ultimately brings us closer to the "truth". (Not everyone agrees, however.)
One thing is certain: There is no certainty in science.