I like your comparison to the Scientist and Theologian,
davem.
I think if we look more at the Scientist perspective of Saruman. What do scientists do? They try to analyze, study, interpret, certain data, and come up with a conlcusion. Come up with an "answer." Light is generally a symbol of "good," opposed to darkness. Looking at the scientifical side, Saruman breaks this "white light," trying to come up with an "answer," trying to find it's secrets, and being Saruman probably trying to find a way to dominate over the "white."
I also, view Saruman's "many colors" as a symbol that he has broken away from the "light." He isn't "white" anymore, he's broken away from the "white/light," and what happens when you do that, the variation of colors. Saruman is no longer "white," anymore, he broke away from it, and now is left with a mass of different colors, they aren't combined anymore to create "white," they are all seperate. I view it as symbolizing that Saruman is no longer pure, he is what "white/purity" is shattered, a bunch of colors.
Edit: Excellent thread topic Lalwende.