If any one saith, that, since Adam's sin, the free will of man is lost and extinguished; or, that it is a thing with only a name, yea a name without a reality, a figment, in fine, introduced into the Church by Satan; let him be anathema.
This canon in particular condemns the false notion that men no longer possess free will (following Adam's fall): as though they are incapable of choosing to do what is right, and are so enslaved to sin that they are constitutionally incapable of doing good. But to say such a thing is as much as to remove culpability for personal sin: we cannot be held liable for things we do under compulsion.
I suspect that the purpose here is to contradict the idea—held by some Reformed types—that to say we have free will is to suggest that a man could conceivably attain salvation by means of his own works. I don't know whose views the Reformed have in mind here, but it's entirely clear that it's not the Catholic view, as we have seen. Having a free will doesn't mean that you can merit justification.