Now four general reasons may be given to prove that happiness consists in none of the foregoing external goods [riches, honors, fame, and power].
First, because, since happiness is man's supreme good, it is incompatible with any evil. Now all the foregoing can be found both in good and in evil men.
Secondly, because, since it is the nature of happiness to "satisfy of itself," as stated in Ethic. i, 7, having gained happiness, man cannot lack any needful good. But after acquiring any one of the foregoing, man may still lack many goods that are necessary to him; for instance, wisdom, bodily health, and such like.
Thirdly, because, since happiness is the perfect good, no evil can accrue to anyone therefrom. This cannot be said of the foregoing: for it is written (Ecclesiastes 5:12) that "riches" are sometimes "kept to the hurt of the owner"; and the same may be said of the other three.
Fourthly, because man is ordained to happiness through principles that are in him; since he is ordained thereto naturally. Now the four goods mentioned above are due rather to external causes, and in most cases to fortune; for which reason they are called goods of fortune. Therefore it is evident that happiness nowise consists in the foregoing.
It is Boethius's account of happiness that gives us the famous image of Fortune's Wheel, by which the fickle goddess Fortune dispenses her favors.