Okay, this is sad. Little did I know that my original comment would create such controversy. I actually know the correct form and usage is “intents and purposes.” For some reason I thought “intensive purposes” sounded better given the rest of my sentence. I call it slang because I have heard the phrasing used before no matter how incorrectly. But again I had already yielded to the fellow commentators in agreement that it was improper grammar. However, I did not foresee the backlash. Several others including you, have already reconfirmed what I already knew that it is indeed “intents and purposes,” and not the other way around. Maybe if I were writing one of my papers, then yes I would understand, but it is clear that those are not the circumstances. What bewilders me is that roughly half of the users on Reddit (by my own approximation) do not even end their post with punctuation? If you want to correct someone perhaps do not call them idiots or suggest that they are stupid? Simply put, I am not going to apologize to strangers over something as minuscule as this. It is sad enough as it is that I wrote this much in response. It sincerely makes me feel discourage to contribute to future conversations, at the very least more hesitant to do so.