Conflict of tenses!

[sseif]

Does the following sentence

"the Iranian revolution showed how poor the ability to predict the future of complex systems is".

contain a conflict of tenses between "showed" and "is" ?

I need your advice

Thanks

[BobK]

There is no conflict. Predicting the future of complex systems IS difficult, and the revolution SHOWED that. Where is the conflictc in that Do you detect any conflict between the fact that gravity affects all bodies that have mass and the story that an apple fell on Newton's head? (The story is dubious, but it's not the sequence of tenses that makes it so )

b

[sseif]

quite convincing

Many thanks