. It isn't induction, because the data on which one would use induction is not being collected until the method is adopted (which is why data appears to be theory laden)
And how does the method adopted prevent induction occurring? What's to stop the method involving induction somewhere? What's to stop induction being part of the theory that 'loads' the data? After all, if inductive reasoning can work well, and can certainly reach conclusions other modes reasoning can't. If there is a pragmatic justification for employing induction - then surely it would be used?
A scientific theory is, primarily, a description of the method rather than a description of the world.
Could you explain how Universal Common Descent is a description of the method rather than a proposed description on the world. As obvious as you suggest this is, most people don't see it. Further, could you show that this is how scientists see what a scientific theory is, rather than just a select group of philosophers?
since the purpose of the theory is to communicate the science
I don't see this as a reason for it to be obvious. Nor do I see any reason to suppose that the sole purpose of a theory is to communicate the science. What does it mean 'to communicate the science'? Do you mean 'communicate the method'?