The Five Usul

I am still reading the book [1].

Summary of pages: 60-64

First Principles: Knowledge of God

It is incumbent on all human beings to exercise speculative reason (al-nazar) in order to know God

the rest of what we need to know about religion can't be known until we first know (rationally) that there is a God

The Qadi names four kinds of evidence on which speculative reason (al-nazar) is appropriately based:
- Rational argument (hujjat al-'aql)
- The Book or scripture (al-kitab)
- The paradigmatic practice of the Prophet Muhammad (Sunna)
- And the consensus of the community (ijma')

The early madhab of Mutazilah identify the following five doctrines
1. Divine unity (al-tawhid)
2. Divine justice or theodicy (al-'adl)
3. The promise and the threat (of reward or punishment in the hereafter, al-wa'd wa 1-wa'id)
4. The "intermediate position" on the matter of who is a true Muslim (almanzila bayn al-manzilatayn)
5. Commanding the good and prohibiting evil (al-amr bi 1-ma'ruf wa 1-nahy 'an al-munkar)

Reference
[1] Martin, Richard C, Woodward, Mark R and Atmaja, Dwi S. 1997. Defenders of Reason In Islam: Mu'tazilism and Rational Theology from Medieval School to Modern Symbol. Oneworld Oxford. Preface. ISBN 978-1851681471