Ask someone what legs are for and the answer comes at once: walking. And why walk? To the shop. Why the shop? For food. Why food? To stay alive. And why stay alive? Here the chain breaks: for the last question we usually have no answer, so we go back to discussing the shop. Śrī Prem Prayojan Prabhu says purposes are arranged like a staircase: the immediate one, the intermediate one, and the final one. The Sanskrit word for purpose is artha; the four aims of human life are called puruṣārtha. The lower steps we keep in mind from morning to night. The top one — the very step the whole staircase was built for — we do not climb for years. He says it out loud: the real purpose of staying alive is to discover God.