Four pillars of faith and unbelief
Nahj al-Balāgha|Volume 1|Book 3|Chapter 31
وَالْيَقِينُ مِنْهَا عَلَى أَرْبَعِ شُعَبٍ: عَلَى تَبْصِرَةِ الْفِطْنَةِ، وَتَأَوُّلِ الْحِكْمَةِ وَمَوْعِظَةِ الْعِبْرَةِ وَسُنَّةِ الاْوَّلِينَ فَمَنْ تَبَصَّرَ فِي الْفِطْنَةِ تَبَيَّنَتْ لَهُ الْحِكْمَةُ، وَمَنْ تَبَيَّنَتْ لَهُ الْحِكْمَةُ عَرَفَ الْعِبْرَةَ، وَمَنْ عَرَفَ الْعِبْرَةَ فَكَأَنَّمَا كَانَ فِي الْأَوَّلِينَ.
Conviction also has four aspects: prudent perception, intelligence and understanding, drawing lessons from instructive things and following the precedents of past people. So, whoever perceives with prudence, wise knowledge will be manifest to him, and to whomsoever wise knowledge becomes manifest he appreciates instructive objects, and whoever appreciates instructive objects he is just like past people.