Archaeology, Forensics, SETI and the Explanatory Filter
Archaeology, forensics and SETI are three active areas of research that propose they can differentiate between nature, operating freely and agency involvement.
But how do they do so?
My claim is that they all use the explanatory filter. My reasoning is as follows:
1- In archaeology you cannot be holding an artifact if nature, operating freely can account for the object. In forensics you cannot have a crime scene if nature, operating freely can account for the evidence. And in SETI they do not infer an alien civilization is sending a signal if nature, operating freely can produce that signal.
So that is the first two decision nodes of the EF- eliminating chance and necessity, ie nature, operating freely.
However just getting beyond the first two nodes is not enough to infer design (nor a crime). You still need some positive evidence. And that is were the third node comes in.
2- In archaeology once nature, operating freely has been eliminated and there is some specification- tool marks, the way pieces fit together, for example- then they infer it is an artifact. The same with forensics- once nature operating freely is eliminated they have to look for things that known agencies can do. And the same for SETI- eliminate nature and then look for something agencies have been known to do.
With living organisms there isn't any evidence that nature, operating freely can produce a living organism from non-livng matter. All scientific data says that life begets life. And yes we observe specification inside of living organisms.
So we have eliminated nature, operating freely and have observed a specification and that is why we infer living organisms are the product of intent and design.