Who has the proof or knowledge that incredibly well-designed natural crystals, the natural arches, or even complicated biological things were designed by someone ‘intelligent’?

From Vinayak

A comment of yours from the article ‘atheism refuted’: “All of us have the knowledge that well-designed things have a designer. “. That is absurd when read in isolation. We know that the airplane is designed by an intelligent man. But we do not have any proof or knowledge that incredibly well-designed natural crystals, the natural arches, or even complicated biological things were designed by someone ‘intelligent’.