Don,
"Don and Lexi" have roles that could continue in the deterministic discussion. Personally I think I would go along with Hume's rejection of logical induction, denying connection to practical reason. I think I point that out in my essay regarding the apparent flirtation of humankind with possible extinction or decision making counter to our well being.
I think Hume also said that "matter in all its operations, is actuated by a necessary force, and that every natural effect is so precisely determined by the energy of its cause, that no other effect, in such particular circumstances, could possibly have resulted from it." My utter speculation regarding dark matter suggests a myriad of interactions produce forces that might be responsible for dark matter. Thus dark matter could be a natural effect of such interactions but certainly is something we have failed to determine.
One thing your essay does is open up the thinking about the impact of mindless laws, the material world and human agency.
Jim Hoover