The article discusses the opinions of two scholars: Nasiruddin al-Albani (a contemporary Salafi scholar) and Sayyid Muhammad Hussein Tabatabaei (a contemporary Shia scholar), on the nature of reason, its kinds and authenticity in religious knowledge. The article reviews their opinions on interpretation with comparison and criticism as possible at the end of each topic. The main point is that the Salafi thought sees the authenticity of perception and tradition, and so it does not rely on reason as an independent source. Instead, it relies on the explicit meaning of religious texts and prefers them reason, without, usually, interpret religious texts. The traditions, that show the authenticity of reason, are not reliable for this school of thought. In contrast, the Shia school of thought sees the authenticity of reason; therefore, this school of thought relies on reason as an independent source, and interprets religious texts while explaining the difference in the meanings of interpretation according to famous opinions. However, reason is a self-evident argument that does not need others to prove its authenticity.