J.G.
Stop arguing with him and play. So when he says it's cold out, remind him to get his coat, or tell him it will be too cold for an ice cream later. Don't argue with him, let him make believe. 4's play with reality. They also are like teenagers, oppositional in exerting their independence.
If I was you, I'd increase floor play time with him, give him lots of extra cuddles and stop arguing.
When my daughter whines or sasses, I remind her that that isn't how we communicate. She quickly changes her tune to get what she wants. Outright defiance gets a TO, fighting TOs get a consequence like no videos or computer time. Her whining and sass has mostly stopped since I started being consistent about how we talk to people, etc.