This paper explores a much overlooked passage buried at the end of the Eudemian Ethics in which Aristotle attributes the success of those he calls ‘fortunate'--eutuchēs-- to nature, a conclusion he would seem not to be entitled to draw. Against the standard view, I argue that we can understand how Aristotle could have quite seriously (and consistently) drawn this conclusion if we distinguish between the proximate cause of the fortunate man’s eutuchia, which is his nature (in particular, his own irrational soul impulses), and its ultimate cause, which is tuchē (because his soul, which contains those impulses, is generated by accident).