Why do Shia hold Aql (intellect) in a higher position in comparison with other sects?

As you possibly know, Aql/Aghl (intellect) is regarded as one of the sources of Fiqh in Islam. In Shia Islam, there are four sources of Fiqh: Qur'an, Sunnah, Ijmaa’ and Aql. (www.wikifeqh.ir ) But as much as I know, Aql is considered as a source which has higher position/place (in Shia's view) in comparison with the view of other Mazhabs (sects). So, my query is that: **What is the reason that Shia (Twelver Shia) hold Aql in a higher position in comparison with other sects?**