Common Design- What is the Point?

-
So what is the point of a common design? The point is, based on direct observations and experiences, that a common design leads to a number of similarities. And that means that universal common descent is A) Not the only explanation for observed similarities and B) May not even be the most parsimonious explanation.

A)- One of the most appealing aspects of universal common descent is that it allegedly explains the similarities observed amongst all living organisms. The thinking goes is that you share many similarities with your parents and that is common descent. However we also know that convergent evolution can also explain similarities- and that is without the concept of a common design.

B)- Parsimony-> well for universal common descent there also has to be quite a bit of change. Change that no one even knows is possible so the concept relies on imagination and eons of time.

That said a common design explains the similarities and the differences are explained by the different applications and differing functional requirements.

All houses built to the same building code(s) will have that degree of similarity and the differences are explained by the customer's wants/ requirements (or even budget constraints).