Of course, it isn’t impossible.
What we really mean is, “I don’t want to put in the time and effort it takes to achieve this big, audacious goal. I don’t have the strength and courage to get back up when I fail. In fact, I know I am going to fail at this for a long time before I see success. I don’t have the guts to push through the dip. It’s stupid anyway. No, I rather stay over here where it is safe. Where no one will judge me.”
It is obvious but worth stating, that human limits are limits defined by humans. Which means they can change—it starts with a posture and an attitude.
Impossible? Perhaps. But more likely, it is improbable, unlikely or has a high chance of failure—This might work.