Intelligent design is eminently falsifiable. Specified complexity in general and irreducible complexity in biology are within the theory of intelligent design the key markers of intelligent agency. If it could be shown that biological systems like the bacterial flagellum that are wonderfully complex, elegant, and integrated could have been formed by a gradual Darwinian process (which by definition is non-telic), then intelligent design would be falsified on the general grounds that one doesn't invoke intelligent causes when purely natural causes will do. In that case Occam's razor finishes off intelligent design quite nicely.

"Is Intelligent Design Testable — A Response to Eugenie Scott", The Golden Spiral, 24 January 2011

https://www.metanexus.net/intelligent-design-testa...[metanexus.net]