The goal of this article is to defend Kant's idea of the highest good as part of his ethics, particularly in relation to the alleged problem of impossibility, according to which it would be impossible to promote it, due to the obscurity of moral intentions and of the relative nature of happiness. As a preliminary step, a singular definition of the highest good is unfolded, one that sees the highest good as a moral world where virtue will be rewarded with happiness, which is a duty and an object of hope, individually and collectively. Regarding the defense itself, a distinction is made between fallible and infallible duties, and a soft interpretation of the "ought implies can" principle (as developed by Stern) is used. The article also points out what is yet required for an overarching defense of the highest good, namely, a response to the other problems at stake, which are here labeled as those of heteronomy (the highest good undermines the principle of autonomy, since it as an object includes happiness), deduction (the highest good is not contained and does not follow from the moral law), and irrelevance (the highest good is irrelevant for ethics). © 2013 Philosophy Documentation Center.