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B. Non-Productivity of money

The second inherent property of *thaman* is its non-productivity: money, qua money, does not produce anything. It does not grow, breed, yield fruit, or generate output by its own nature. Al-Sarakhsī states the principle with ontological precision: "money cannot generate benefit while preserving its substance" (*al-nuqūd lā yumkinu al-intifāʿ bihā maʿa baqāʾ ʿaynihā*).[^17] Ibn Taymiyya draws the consequence: "seeking profit from money-exchange without manufacture or trade, this is *ribā*" (*ṭalab al-ribḥ fī al-muʿāwaḍa bi-l-nuqūd min ghayri ṣināʿa wa-lā tijāra, hādhā huwa al-ribā*).[^18]

The non-productivity property grounds the grammar's treatment of interest-bearing loans as prohibited: if money cannot produce by its own nature, then a surplus demanded in exchange for the loan of money compensates for nothing but time, which is an operator, not a primitive. The surplus is the price of temporality, a Type 1 category violation. This is not a rule imposed on money from outside; it is a consequence of money's inherent nature as a measuring instrument that lacks productive capacity. A tool (*ʿayn*) can be leased because it generates *manfaʿa* (use-value) over time. Money cannot be "leased" because it does not generate use-value while preserving its substance; its use consists in spending it, which is its destruction as a monetary unit in the holder's possession, not the extraction of benefit from a persistent asset.