That's not technically true, actually. The word "instinct" is one of those scientific terms that tend to get thrown around a lot in incorrect contexts. Scientifically speaking, we only have a few actual instincts left in our wiring-- language, play, and imitation being chief examples. However, this does not in any way preclude the debate over the predictability of human nature. Just because we're not acting primarily on instinct doesn't mean that our minds are blank slates, and I would certainly be among the first to argue that human nature is a relatively inescapable pattern.