WT 1981 12/1 pg. 28 paragraph 9.
" Such adjustments might be said to follow a principle that has been said to govern the progress of scientific truth. In brief, it works something like this: At first there is a proposition made that is subject to argumentation. It holds out great possibilities for enlightenment or practical application. But then in time it is seen to have certain flaws or weaknesses. So the tendency is to go to a proposition at the opposite extreme. Later it is found that that position does not represent the whole truth either, and so there is a combining of the valid points in both positions. Time and again this principle has applied in the way Proverbs 4:18 has been fulfilled. "