The Infallible Imams (`a) and Mental Sciences
Human being is wise. He uses his wisdom and logical measurement to discover some unknown things from his definite general data. Human, for instance, understands the cause-effect relationship and that everything requires a cause. Therefore, when he sees something, he is certain that it has a cause and seeks that cause. This is a privilege for human being, which is idiomatically called theoretical mentality. Such mental reasoning is used in proving belief principles, such as theology, Resurrection, or prophet hood. All humans have the Divine blessing of mentality, but their intellectual levels are very different. The prophets (s) and the infallible Imams (`a) have been the wisest of the people in their own age.
The Messenger of Islam (s) states, “The Almighty Allah did not send a prophet or messenger except when his wisdom was perfect and superior to that of his people.” 
The honorable Messenger of Allah (s) used his perfect wisdom in understanding belief principles, such as theology, Resurrection, and human need to prophets’ guidance sent by the Almighty. In fact, he believed in these facts through his mentality. Therefore, he had certainly believed in Allah even before his appointment and hated disbelief and polytheism. It should be pointed out that mental belief –the belief that is acquired by pondering– is not beyond conception and acquirable knowledge, even if it reaches certainty.
After being appointed to prophet hood, direct relationship with the unseen world, and receiving revelation, however, Prophet Muhammad’s (s) mental belief got beyond meaning and reached the level of intuition. In this level, he observed the facts that cannot be understood with conceptual knowledge. Intuitive knowledge and heavenly observations of Prophet Muhammad (s) can be considered as a support for his mental sciences. The belief and heavenly sciences have special effects that do not exist in case of mental sciences. The infallible Imams (`a) –as testified in the history and their traditions– have been the wisest of the people in their own age. Therefore, they perceived sciences related to Creation and the Resurrection by their perfect mentality. They were away from disbelief and infidelity even before being appointed for Imamate. These chosen people did not receive the revelation directly, but they benefited from the Prophet’s (s) heavenly sciences indirectly due to Allah’s especial blessings and Prophet Muhammad’s (s) guidance. As a result, their knowledge about the Creation and the Resurrection was above conceptual science and had reached the level of intuition and certainty. They sometimes talked about Creation- or Resurrection-related facts in a way as if they directly observed them. Some examples of this manner can be studied in tradition, biography, or history books.
Amiral Mu’minin, Imam Ali (`a) stated about knowledge of the infallible Imams (`a), “Knowledge has been perceived by their insight and they have touched certainty. They have easily accepted what is considered difficult by the mollycoddle and are accustomed to what the unwise fear. They relate with the bodies whose souls have ascended to the Heavens. They are Allah’s caliphs on the earth and inviters to His religion. How much I desire meeting them!”
Imam Ali (`a) also stated about the sciences of infallible Imams (`a), “They revitalize knowledge and perish ignorance. Their patience reveals their knowledge and their appearance shows their inside. Their silence is a sign of their strong logic. They do not oppose the truth and have no difference about it. They are pillars of the religion and refuge of the people. They replace the falsehood with the truth, drive falsehood away and abandon it forever. They ponder on and use the religion as it deserves, not merely hearing it and narrating for others. In fact, narrators of science are many, but its guardians are few.”
The infallible Imams (`a), just as prophet Muhammad (s), used mental and logical methods in inviting people to the belief principles, as is seen in their traditions and discussions. They talked to everyone as much as his recognition and understanding. Some of their words are so deep and complicated that are only understandable for the scholars. However, they sometimes speak so simply for the ordinary people. These different speech styles can be found in Imam Ali’s (`a) Maxims in Nahjul Balaghah as well as various traditions of infallible Imams (`a).
As a result, the wisdom of the infallible can be considered a science source of the Prophet (s) and Imams (`a). Mental and logical reasoning is their propaganda method too. Of course, they were way from fallacy and wrong doing in deploying these tools.
 Mizanul Hikmah, Vol 3, p. 2034.
 Nahjul Balaghah, Maxim 147.
 Ibid, Maxim, 239.