Now, imagine we confront someone who holds some end E, believes some means M is necessary for E-ing, yet doesn’t intend to M, and, like the Tortoise, doesn’t intend to M because he refuses to apply instrumental rationality to the ends he has, including E.  If we suggest that he remedy this defect by adopting yet another end (namely, the end of doing what instrumental rationality requires), this wouldn’t help matters.  Since his problem is that he doesn’t apply instrumental rationality to the ends he has, he wouldn’t apply instrumental rationality to this new end as well, and so still wouldn’t intend to M (or drop the intention to E).  So, the mere addition of instrumental rationality as another end would be futile.