verbal objections, while others concern substantive matters. Regarding the argument he had presented on their behalf to establish the First Cause, he said:

“This argument is persuasive but unsound, for the term ‘cause’ is applied equivocally to the four causes, namely: the agent, the form, matter, and the end.

“Likewise, if this were the philosophers’ answer, it would be defective. They would be asked which cause they meant by saying that the world has a first cause. If they said, ‘We mean the efficient cause whose act has always existed and will always exist, and whose effect is its very act,’ this would be a sound answer according to their doctrine and, as we have explained, not open to objection.

“If they said, ‘We mean the material cause,’ their statement would be open to objection. Likewise, if they said, ‘We mean the formal cause,’ it would be open to objection if they posited the form of the world as subsisting in it. But if they said, ‘We mean a form conjoined with matter,’ their statement would accord with their doctrine.