3.322 A common characteristic of two objects can never be indicated by our symbolizing them with the same signs, but by two different ways of symbolizing. Because the sign is indeed arbitrary. One could thus also choose two different signs and where would then be what was common in the symbolization?
So, for instance, that we both call something by the name “God” does not at all mean that we are talking about the same thing. The word used is arbitrary, just as it would (probably, etymological curiosities aside) be pure coincidence if a word in two historically unrelated languages looked or sounded exactly the same. What matters is the way in which the word means. What matters, one might say, is its use.