Error: an object reference is required for a non-static field, method, or property "MouseLook.Enabled"

This is my code. MouseLook is the class that I want to set Enabled from, Enabled is a bool. if (Input.GetKeyDown (KeyCode.Escape)) { Paused = !Paused; if (Paused) { MouseLook.Enabled = false; Time.timeScale = 1; NGUITools.SetActive (PauseMenu, false); } if (!Paused) { MouseLook.Enabled = true; Time.timeScale = 0; NGUITools.SetActive (PauseMenu, true); } }