The paper is aimed at examining the issue of the sustainability praxiological paradigm, which seems to be the best (maybe, the single) alternative to replace the optimality one, under the pressure of the current (perhaps, wrong) path of mankind within the ideology of capitalism. The analysis has a general and abstract character, the basic methodology being the logic. The paper focuses on the societal level, not the economic field only. The fundamental features and principles of the sustainability model of rationality are identified and evaluated, so a two-handed pattern of this paradigm is proposed. A generous space is allocated to examine the crisp inconsistency between the proposed sustainability ideology and the current capitalist ideology, so Ordoliberalism is identified as the most adequate political philosophy capable of irreversibly objectifying the sustainability model of rationality at the societal level.