Stallman said that free software is software that is freely accessible, free to modify, free to share with others, and free to change and redistribute copies of the changed software.
As for non-free software, Stallman has no patience for it.
"Any non-free program is wrong. A non-free program gives the developer power over the users and that's not excusable so it's always wrong," he said.
Software should be free. What Stallman is talking about is free as in freedom - not free as in free beer Fridays.
"If it is a non-free program," Stallman said, "it attacks your freedom whether you pay for it or not."
He explained that, "Merely getting a chance to try it for 30 days is absurd. Why should you try it for even a second, if it's going to attack your freedom?"
And what about patents? Forget about it.
"Every patent is a monopoly on using a particular idea," he said that is antithetical to freedom as well.