At 19 months old, Helen Keller, due to an illness, became both blind and deaf. With the help of a teacher, Anne Sullivan, she was able to accomplish great things, becoming an author, political activist, and lecture. She was the first deaf/blind person to earn a Bachelor of Arts degree.
I imagine that none of us has experienced and overcome these kind of obstacles. At issue here is doing it alone. No matter what we do, we need people to help us along the way, no matter how independent we think we are.
Try flying across the country. Look at the number of people who have been involved in making that flight possible from the people who developed the airplane to those who designed and built your airplane, flew the airplane, kept your flight safe and, delivered the correct baggage to you.
Life takes teamwork, people working together toward a common goal. No matter how self important we think we are, we can't successfully do it on our own.