There is evidence all around us of intelligence beyond human grasp. Remember, these incalculably complex systems supposedly just arose from a primordial soup one day.
Ask an atheist why our universe is undeniably fine-tuned for life. Out of a septillion possible outcomes, this one exists, where matter exists, where enough matter exists to create gravitational wells so stars and planets form. The weak atomic force, strong atomic force, electromagnetism are all perfectly balanced for physical matter to form complex arrangements. But gravity is insanely weak, allowing matter to accrete around stars and form planets. And yet gravity is powerful enough to fuse Hydrogen and Helium into higher elements, which can then gather on planets to mix together in complex chemical interactions to yield life.
Stars are powerful, but not so powerful to evaporate the planets. Etc.
The sheer unlikelihood of all this is beyond calculation. I'll wait for an atheist to respond with the 'explanation' for this so I can BTFO him.