Says who? Based on what?

You are seriously underestimating one of the hardest questions ever posed and for which there is no (and there may never be) definitive answer. Tabula rasa, genetic determinism, nature vs nurture, etc are all deep, hard problems.

As a matter of fact, can you even significantly define “desire” or “instinct”? A lot of smart people have tried in the last 2500 years and there is no consensus yet.