Iqbal traces the arc of revolt against juristic finality from Ibn Taymiyyah through al-Suyūṭī to the eighteenth-century Wahhābī movement, which he calls 'the first throb of life in modern Islam.' But he withholds full endorsement: the Wahhābīs asserted the right of independent judgement without exercising it critically, achieving formal but not substantive ijtihād.
Section 2 diagnosed the three causes of ijtihād's closure — the conservative reaction against Muʿtazilite Rationalism, the absorption of the best minds into Sufi otherworldliness, and the defensive rigidification following the fall of Baghdad — and closed by naming Ibn Taymiyyah as the 'powerful reaction' that the inner impulse of Islam generated against this immobility. Section 3 now traces the arc of Ibn Taymiyyah's intellectual programme through its historical consequences: his own revolt against the finality of the schools, the sixteenth-century claim of al-Suyūṭī, and — most significantly — the eighteenth-century Wahhābī movement, which Iqbal calls 'really the first throb of life in modern Islam.'
The section advances through three connected arguments. First, Iqbal describes Ibn Taymiyyah's substantive positions: his rejection of analogical reasoning (qiyās) and of ijmāʿ as conventionally understood, and his insistence on returning to 'first principles' — the Qur'an and Sunnah, unmediated by the accumulated authority of the schools. Second, Iqbal traces the genealogy of this impulse through al-Suyūṭī to Muḥammad ibn ʿAbd al-Wahhāb, whose movement Iqbal treats as the most consequential expression of Ibn Taymiyyah's spirit — the source, 'directly or indirectly,' of 'nearly all the great modern movements of Muslim Asia and Africa,' including the Sanūsī movement, the Pan-Islamic movement, and even the Bābī movement in Persia. Third, and most importantly, Iqbal delivers a carefully calibrated evaluation: the Wahhābī movement is admirable in its 'spirit of freedom' and its vigorous assertion of the right of private judgement, but it is 'inwardly conservative in its own fashion' — its 'vision of the past is wholly uncritical,' and in legal matters it merely substitutes the authority of ḥadīth for the authority of the schools, without achieving the genuinely creative ijtihād that the situation demands.
This third movement is the section's philosophical centre of gravity. Iqbal is making a distinction that is essential to the entire argument of Lecture VI: the distinction between formal and substantive ijtihād. Formal ijtihād rejects the authority of the schools and asserts the right of independent judgement — but then exercises that judgement in a way that is itself uncritical, falling back on a literalist reading of the primary sources rather than engaging them with the creative, reconstructive energy that genuine ijtihād requires. Substantive ijtihād does not merely reject inherited authority; it generates new intellectual frameworks adequate to new circumstances. The Wahhābī movement achieved the former but not the latter — and this limitation, Iqbal implies, is why the 'immense potentialities' of the movement were never fully realised.