Tibby, you are right - on the whole. However, I'd like to take this as a start point:
A Scientific law defines how nature will react in a situation, while a Theory is normally an all-encompassing explanation as to why these laws work.
I'm going to flex my muscles a bit here. Some are born to teach, whereas some are designed and bred to be teachers of teachers.
An expert knows of things. His knowledge is born out of a desire to know and a respect of authority. His methods are clear and precise. And he will always be good at passing exams and assesing situations and finding a good solution.
There is, something that he lacks; in actual fact something he doesn't look for. And that is intuition, or creativity.
The scientist, exactly the same as an artist, for that's what all true discoverers are; is a person who actually looks for patterns, observations and then synthesises them to create theories.
Some are simple; we can go back to Egyptian/Ancient Greek days and note the patterns of their findings; Pythagoras' rule. Later Archimedes principle. Simple 'laws' that came about from someone saying...now 'I wonder' or 'thats strange'.
Laws are never really laws; they just happen to hold up against the test of time so far. The heart of the theorist; the guy who actually 'thinks' of these things the majority of the time mostly feels of something that ends up as a blocked path, a stub in the eye, or is simply wrong. But with enough awareness, skill and determination, there will be something found; so long as you stick with a problem for sufficient time.
And that's how creativity is the heart of the theorist; and how there are no such things as 'law' but just ideas that are carved over time and that stand up to testing more so than others. If you check back at the original quote, as brilliant as it is, I would modify it to "a theory is an all-ecompassing explanation of how a thing or process is perceived to operate". The law tag comes after and even then; we must mark a difference between science that builds and science that revolutionises. That difference comes from the person that understands the difference between nature as his source; and education as his source. The best of the best, know both
nb: to bring this back to evolution; I think that change, for now, is true. For evolution is really just the positive subjective of change. Devolution and evolution are aspects of change due to process. Its how these processes operate that science carves down to essences and, in turn, its how these essences are used that determine the future.