Incompatible Trilemma Arguments

I have always appreciated the structure of the classic “problem of evil” argument – appreciated it on aesthetic and elegance grounds.  You perhaps recall the general formulation: all powerful, all knowing, and all good.  Any two are compatible with the existence of evil; not all three.  There are many forms of argument roughly set up in this way; this one says that the three taken together are incompatible with an additional condition, the existence of evil.

Another related structure of argument is that any two conditions are compatible, but not the third, as among the three of them (even without reference to a fourth condition).  And so on.  So, just on elegance of structure alone, I appreciated Professor Mankiw’s NYT column from yesterday, setting out the classic argument over incompatible policy goals in international economics, The Trilemma of International Finance:

What is the trilemma in international finance? It stems from the fact that, in most nations, economic policy makers would like to achieve these three goals:

  • Make the country’s economy open to international flows of capital. Capital mobility lets a nation’s citizens diversify their holdings by investing abroad. It also encourages foreign investors to bring their resources and expertise into the country.
  • Use monetary policy as a tool to help stabilize the economy. The central bank can then increase the money supply and reduce interest rates when the economy is depressed, and reduce money growth and raise interest rates when it is overheated.
  • Maintain stability in the currency exchange rate. A volatile exchange rate, at times driven by speculation, can be a source of broader economic volatility. Moreover, a stable rate makes it easier for households and businesses to engage in the world economy and plan for the future.

But here’s the rub: You can’t get all three. If you pick two of these goals, the inexorable logic of economics forces you to forgo the third.

Professor Mankiw goes on to point out that the United States, China, and Europe have each chosen a different set of two in the trilemma – and part of the political and economic pressure they put on each other reflects those preferences.

But back to the form of argument – it is something that shows up sometimes in formulating arguments in the law and other places.  Other instances of recourse to this kind of argument form?  (I seem to recall that corporate law scholar, Dean Bob Clark, used something along these lines in a corporate law setting once.)