"Hence it happens that one takes words for concepts, and concepts for the things themselves"

This quote by Johann G. Hamann is a tip that words and concepts are not the same thing. Words are signs that represent ideas, but they are not the same as the concepts themselves. Principles are abstract concepts that are not concrete, while words are concrete signs that represent those ideas. This quote is a pointer that we must not confuse words with principles, and that we should beware not to take words for concepts. We should aim to comprehend the principles behind the words, and not simply take the words at face value. This quote is a suggestion that words are not the same as the principles they represent, which we should make every effort to comprehend the principles behind the words.