Question.....

What’s the difference between an involuntary reflex and natural instinct?

Isn’t reflex something along the lines of pulling away from something hot, where as natural instinct is something more like finding shelter. (in animals anyways)
(What I’m thinking is that a reflex is just that, a reflex, whereas an instinct is more of a process used for survival, eating, finding shelter)

Is this a homework question?

But pulling away from something hot is a voluntary reflex. Reference the monks many years ago setting themselves on fire in protest of the Vietnam war.

Maybe I should revise the original question: Do we, as Homo Sapiens, have natural instinct?

No, keeping your hand in a fire is voluntary, the initial flinch to yank it out when you didn’t expect to get burned is involuntary.

As for people, I think examples of natural instincts would be that of babies recognizing faces or ability to crawl. No one teaches them these things, but they all do it quite well.

I would guess that for adults the instinct to mate would be arguably a natural instinct. I don’t know if one would know what to do without having lived in a social group (a la Blue Lagoon), but my guess is that two adults with no previous knowledge of sex would figure it out. Just my WAG.