he does not prove that his four elements exist, and he defines them badly; his elementary qualities are not as he claims, he does not know their nature, and the secondary qualities are not all composed of the elementary ones; finally, even if one grants him that all bodies are composed of the four elements, as the secondary qualities are from the primary, his whole system would be useless in the search for truth, since his ideas are not sufficiently clear to preserve the evidence in our reasoning.