Here we begin to understand why it was necessary to dwell on the principles of Catholic morality earlier in our study. We observed that man’s concrete action and the will behind the action must both be conformed to the good in order for the act to be moral. If self-interest is in itself unhealthy, it does not matter if it produces vast amounts of wealth for the world. We may not do evil that good may come of it, and that is all there is to it. There is no praise for the man who “unintentionally” helps society when his only conscious choices were to help himself. The doctrine of self-interest fails not because it lacks productive value (although arguments could certainly be made that it fails here as well), but because of the habit it instill in the soul. For what good is it for a man to gain the whole world, yet forfeit his soul? 
 See section on Morality above.
 Mk 8:36.