Can We Detect Design Without Knowing the Identity of the Designer?

Recently an atheist student emailed me to ask how it's reasonable to claim that an "unobserved designer" is responsible for complex features of nature, like high CSI (complex specified information) and irreducibly complex structures. In reply, I explained that first we must ask the question "What does it mean to 'observe' or 'detect' something?" Here's a start: Our eyes can help us observe objects in nature by seeing light reflected from those objects. Our ears can help us detect objects in...