Chisholm was fascinated by Brentano’s Thesis. He published a series of papers on the topic, starting in 1952 and carrying on until at least 1981. In his papers Chisholm formulated precise versions of Brentano’s thesis. Each paper provoked critical reaction from other philosophers. Since in some cases the criticisms were cogent, Chisholm was motivated to develop new and more ingenious versions of the Thesis.