Let me once again summarize the argument that we have made so far. Individuals determine the level of innovation under the Knightian uncertainty in accordance with the max-min rule in order to maximize their own benefits. The level of innovation thus determined mostly matches that of innovation on a society-wide basis that has been agreed by people in the "original position" under the difference principle (max-min rule). This suggests that the level of innovation pursued as part of the activity of individuals to pursue their own ends (individual virtue) matches that of innovation pursued under the society's concept of justice. In other words, it has been shown that the level of intellectual investment (innovation) made selfishly by individuals in accordance with their own life goals inevitably matches that of the innovation that should be realized in order to enact the concept of justice shared by the society as a whole.
Different people have different life goals, and activities they conduct in order to selfishly pursue their goals may entail innovation in some form or other, which results in the advancement of social justice. Until recently, doubt over the everlasting progress of reason has in turn created doubt over the significance and perpetuity of innovation. However, the explosive evolution of artificial intelligence driven by deep learning has now made it possible to believe that innovation resulting from the power of "expanded reason" will continue to make progress indefinitely.
We assume that we have succeeded in presenting a comprehensive doctrine by introducing intellectual investment (innovation) made by individuals into the Rawlsian concept of justice. Like popular economic theories, such as Adam Smith's theory of "the invisible hand" and Bernard de Mandeville's theory that private vices lead to public benefits, our comprehensive doctrine may be interpreted as implying that the selfish activities of individuals unwittingly contribute to society-wide public good. By introducing innovation as a key element, Rawls' theory of justice can be developed into a "moderate" comprehensive doctrine that is similar to popular economic theories.
The Rawlsian concept of justice (particularly the concept of distributive justice brought about by the difference principle) ultimately converges toward a perfect form of justice through constant rethinking in accordance with increases in and updating of mankind's scientific knowledge. The concepts of virtue that individuals maintain unwittingly but inevitably contributes to the society's concept of justice. As a result, the value of such concepts is based in and justified by the society's concept of justice. Moreover, individuals can believe in the inevitability of progress—that is, they can believe that whatever life goals they may choose, those goals contribute to the advancement of social justice through innovation.
The findings of Smith and Mandeville in the field of economics have increased the significance of economic activity by fostering the belief that individuals' selfish economic activity is justified by society-wide justice, as does our argument. Increasing the social significance of economic activity was what they aimed to achieve.
The objective of the economic activity of individuals is to maximize their own benefits (or economic profits), but pursuing that objective was often seen as a shallow and vulgar life goal; at least, most intellectuals in the era of Smith and Mandeville must have felt that way. However, even though attempting to maximize one’s own profit may be vulgar, that behavior itself contributes to public good in the form of an additional increase to the benefits that other people receive. That was what Smith and Mandeville found. As a result, the apparently vulgar behavior of seeking to maximize profit has come to be approved by the whole society (as it advances public good) and to be recognized as a noble activity. Maximizing profit for one's own sake has ceased to be seen as a disgraceful goal and has come to be seen as an activity that deserves to be a legitimate subject of academic study. In this way, "economics" was established as a field of academic study for the first time.
In making our argument in this article, we are attempting to do in the field of Rawlsian political philosophy what Smith and Mandeville achieved in the field of economics. What individuals aim to achieve in their life may be in itself vulgar and insignificant and appear unlikely to be justified by social justice. On the other hand, individuals can only believe that their lives are worthwhile if their life goals are justified by social justice. However, under the political philosophy of Rawls' theory of justice, individuals' life goals could not be justified by social justice because individuals' own particular goals were assumed to be entirely disconnected from social justice.
We have demonstrated that individuals' pursuit of their own goals contributes to the advancement of some aspects of public good (expansion of justice) by raising the intellectual level of the society through the creation of innovation. Pursuing selfish goals unwittingly advances social justice through innovation. Therefore, individuals pursuing their own life goals according to their own desires and passions can inevitably be considered socially valuable.