Hi A.,
My now 25 year old was much the same way! The thing is, you can't reason with a child this age. You do, however, need to be consistent and firm. I know it can be very tiresome, but if there's no consequence, there's no change in behavior. What behaviors are you trying to stop? At that age, their little brains are at the highest activity of their lives. It's hard to tell you what to do, but I'll tell you what worked for me:
1) Choose the battles--ignore the small stuff. I tried to give choices when possible so she felt that she had some control.
2) Praise when the child is being good. He could be being naughty to get attention--my Paige did!
3) A wise pediatrician with 5 kids of his own told me to put Paige in her crib when she was out of control. I would calmly tell her that she couldn't do whatever got her into trouble, tell her that she could come out when she calmed down, leave the light on, and shut the door. Yes, everything in the crib would be on the floor. It didn't take long for her to learn that the tantrum wasn't going to get attention. And no--we never had a problem with her associating the crib with a place of punishment. She always went to bed at night without a problem. Eventually, she learned to sit in the corner for a time out.
I'll be that your little guy is really smart. When he learns to talk more, things will get a lot better. Remember, there's nothing wrong with "Because I'm your mother and I said so!" Good luck! (My grandkids call me GJ for Grandma J..)