Richard...perhaps the 'saying' is "there are no truths in science"?
Newton's LAWS of motion. It has been tested and proven. So yes, there are truths in science.
Richard was trying to say that new understandings of our universe are built upon old understandings. It's not to say that these old understandings were wrong. In fact, they were correct, but did not maybe apply to the entire picture.
Like Richard (I think) said,
1915: Einstein's General throry of relativity BUILDS UPON Newtonian physics and gives us a new, more intricate understanding of the universe. Newton could calculate where a planet should be with tremendous accuracy, however he did not know WHY it was there. That is what einstein taught us.
In the 1920's quatum mechanics(led by Neils Bohr amongst others) showed that Einstein's view of the universe was limited. His equations only worked on large objects, but broke down at the atomic level. Quantum mechanics had a solution for this. However Einstein did not like quatum mechanics and did not take well to it. However, the PEER-Review process showed that Quantum mechanics was indeed reall, and that in fact the particles that make up our bodies are everywhere in the universe at the same time. Peer-review did not care that a genius like Einstein did not think this theory was right. So no, it is not individuals that necissarily are at the heart of science, it is the peer-review collection!
Right now physicists think string theory might be the answer to unite the world of small and the large. We do not know if they are right yet, however, even if they are it does not discredit what Newton, Einstein, or Neils Bohr did previously. What they did was right in certain scenarios, but ultimatley something new will come along that will build upon their knowledge and give us a more complete view of the world we live in.