Iqbal turns to the existential case for the timeliness of religion: the same idea of evolution produced Rūmī's ecstatic vision of man's limitless ascent in the world of Islam, and a hopeless verdict that human endowment will never be materially exceeded in modern Europe. Even Nietzsche, who tried to sustain a forward-looking vision, collapsed into the doctrine of eternal recurrence — which Iqbal diagnoses as the same old idea of being masquerading as becoming.
Section 3 presented the first reason for the timeliness of the question 'Is religion possible?' — the scientific case: modern physics, by its own internal development, has acknowledged that its picture of reality is partial and that 'feelings, purpose, values' lead somewhere beyond the world of space and time that science describes. Section 4 now presents the second reason: the practical or existential case. Modern civilisation, for all its mastery over nature, has been robbed of faith in its own future. The idea of evolution — the same idea — has produced diametrically opposite effects in different civilisational contexts: in the world of Islam, Rūmī's ecstatic vision of man's limitless spiritual ascent; in modern Europe, the despairing conclusion that 'the present rich complexity of human endowment will ever be materially exceeded.'
The section advances through two movements. First, Iqbal sets up the contrast between Rūmī's evolutionary optimism and Europe's evolutionary despair. The contrast is not merely aesthetic; it is diagnostic. The same biological fact — the emergence of complex life through a process of development — generates hope or hopelessness depending on the metaphysical framework within which it is received. Within the Islamic framework, where the universe is the creative self-disclosure of a purposive Ultimate Reality, evolution points forward and upward: man is not the terminus of the process but a stage on the way to something higher. Within the naturalistic framework, where evolution is a purposeless mechanism driven by random variation and natural selection, there is no reason to expect that the process will continue to produce anything better than what already exists.
Second, Iqbal addresses the apparent exception of Nietzsche — who did believe man could be surpassed (the Übermensch) — and diagnoses Nietzsche's failure. Nietzsche's enthusiasm for the future of man 'ended in the doctrine of eternal recurrence — perhaps the most hopeless idea of immortality ever formed by man.' Eternal recurrence is not genuine becoming but 'the same old idea of being masquerading as becoming': a closed circle that merely repeats the same finite content infinitely, offering the appearance of duration without the reality of creative advance. This diagnosis of Nietzsche reprises the critique developed in Lectures I–II (where Iqbal distinguished genuine duration from mere serial repetition) and anticipates the extended treatment of Nietzsche in Section 9.
The section's philosophical stakes are high. If Iqbal is right that naturalism leads inevitably to despair about the human future, then the question 'Is religion possible?' is not merely a theoretical inquiry but a civilisational emergency: without religion (in Iqbal's sense of experiential contact with Ultimate Reality), modern civilisation has no basis for hope.