Either way, an Aramco I.P.O. raises questions, and what investors don’t know about the company — the accuracy of its claimed oil and gas reserves, for instance — is only one of them. An investment in Aramco would also be an investment in a kingdom that systematically represses women, and hence, in human and social capital. None of the many officials named to new posts in the decrees were women.

Though ostensibly aimed at modernization, neither the development plan nor the decrees propose changes in the kingdom’s basic political arrangements, in which religious fundamentalists uphold the legitimacy of the royal family in exchange for freedom to foster and spread extremist ideology. There is also no explanation of how even a big infusion of cash would build new industries from nothing and transform Saudi Arabia’s estimated 20 million subjects into self-supporting employers and employees.

Moody’s Investors Service, the credit rating agency, alluded to all that when it downgraded Saudi Arabia a week after the decrees were issued, citing the kingdom’s reduced ability to “weather future shocks” in the face of lower growth, higher debt and dwindling financial reserves low oil prices. In Moody’s view, it is too soon to tell if the new plan will revive the credit rating or if the proposed reforms can be achieved without causing social unrest.

Saudi Arabia desperately needs to modernize, and even talking about that need is a step forward. But neither the Saudis nor their global bankers should pretend that an I.P.O. of Aramco, as the company is currently configured, is a viable means to that end.