How is that circular logic?
One is a claim. Specifically that there is utility to biological life.
The other expresses doubt to your claim. Specifically that natural rights are thing that actually exist.
In order for my argument to be circular one would have to depend on the other and then that one would depend back on the first. These are two separate and distinct arguments. In fact yours appears to be circular.
Natural rights are inherent in human biological life and so human biological life has natural rights. That's a circular argument. It's why I asked you to describe to me the
utility of these rights. If you can demonstrate it affects something other than itself then you're a little bit closer to proving it actually exists.