: In 1878's ‘How to Make Our Ideas Clear’, Peirce states that truth is the predestinate opinion, or that which is fated to be ultimately agreed to by all who investigate. Later in his life, though, he would claim both that truth is what would be believed if we could figure out the right method of inquiry and that, instead of affirming that truth is the predestinate opinion in 1878, he ought to have affirmed that truth is what would be (...) believed if inquiry were carried sufficiently far. The aim of this paper is to provide an account of why the early Peirce endorses the claim that truth is the predestinate opinion and why the late Peirce is compelled to modify that position. I argue that Peirce's early statement that truth is the predestinate opinion is motivated by his theory that all mental action is of the nature of a valid inference and that the later modification of his view is partly motivated by his rejection of that theory. (shrink)