I have heard there is some fairly recent result showing that whenever theories $T$ and $T'$ have the same consistency strength, then each can interpret the other. I suppose it refers to first order theories, and I do not know exactly what kind of interpretability it uses or what measure of consistency strength.


Can anyone give me the result, or point me in a good direction?



Interpretability and consistency strength
John Steel spoke at the EFI series at Harvard concerning his ideas on [The triple helix](http://logic.harvard.edu/EFI_Steel_TripleHelix.pdf), which has to do in part with the interplay of large cardinal strength and the arithmetic interpretability hierarchy. This is not exactly the claim you mention, but there is a family resemblance.


