I will once again begin a discussion from the viewpoint of the Rawlsian liberal philosophy. Under liberal political philosophy, human activity that triggers changes in scientific knowledge, i.e., innovation, has not been held in the highest regard. However, changes in scientific knowledge could significantly change the social system. That is particularly true regarding distributive justice. If this matter is considered under the framework of the Rawlsian political philosophy, changes in scientific knowledge may cause significant change to the application of the difference principle. For example, in 1971, when Rawls' A Theory of Justice was published, global warming was a mostly unknown phenomenon outside of expert circles, but now, it is widely recognized as an important policy challenge that mankind must resolve. Society’s concept of distributive justice regarding intergenerational distribution will change considerably depending on whether the difference principle is applied on the premise of the scientific knowledge that was shared society-wide in 1971 or on the premise of the scientific knowledge available 50 years later. In other words, the updating of scientific knowledge through innovations leads to the upgrading of the concept of justice by changing the consensuses formed in the original position under the veil of ignorance. To sum up, the motivation of humans and companies to engage in innovation activity is based on their pursuit of special interests based on their own desires and passions. However, the end result is that innovation creates new knowledge, which spills over to and freely circulates throughout society through people's learning processes. This phenomenon, called knowledge spillover, updates the collective knowledge of society. The society-wide common knowledge level is a precondition for people to agree to the social system under the veil of ignorance, which means that innovations change the system of a fair society.
This relationship presents an opportunity to connect individual virtue and social justice.
Innovation can be broadly defined as a quest for knowledge and investment in knowledge including activities of individuals and companies that cause changes in scientific knowledge. All activities conducted by people are intended to provide a better understanding and allow them to more effectively influence the world in order to achieve their respective goals. As innovation is an activity that is undertaken to find ways of better understanding and more effectively influencing the world, it may be said that all human activities involve innovation.
Innovation as defined in this article, unlike in the usual sense of the word, refers not only to engineering technology development and scientific invention and discovery, but to a quest for knowledge in the broad sense. Activities conducted by ordinary people in their daily lives, including those intended to "better understand and more effectively influence the world," are widely considered innovation in this article. Innovation in this sense includes intellectual discovery and invention that anybody may experience in everyday life or working life.
Innovations update the collective scientific knowledge of society through knowledge spillover. Under updated scientific knowledge, the social concept of justice is accordingly renewed. In a society where the concept of justice is determined by the principles of the Rawlsian political philosophy, each time scientific knowledge changes, parliament is convened (the Rawlsian original position is modeled on a parliament where individual parliamentarians engage in debate as the representatives of the general public with no regard to the special circumstances of their respective constituencies). In this parliament, a new system of distributive justice is determined as a result of the application of the difference principle to new scientific knowledge.
In this way, a quest for knowledge conducted as a private activity by individuals and companies, that is, innovation, enables the social system to progress. The more accurate the scientific understanding of the world becomes, the closer the social system moves toward completion.
