Disease is an impediment to the body, but not to the will, unless the will itself chooses. Lameness is an impediment to the leg, but not to the will. And add this reflection on the occasion of everything that happens; for you will find it an impediment to something else, but not to yourself.
Epictetus
People throughout history have shown us that the only thing stopping us is ourselves. Look at Helen Keller, who was blind and deaf at 19 months old. She earned her bachelor's degree, authoring fourteen books amongst other writings, while traveling the world doing campaigns for people with disabilities, women’s suffrage, labor rights, and world peace. What about Viktor Frankl, who wrote the famous book “Mans Search for Meaning” after being sent to concentration camps nine months following his marriage? Within his three years there, his father, mother, brother, and wife would all die from gas chambers and illness. After the war, he continued his work and study in psychiatry. He even returned to college and earned a Ph.D. in philosophy and a professorship in neurology and psychiatry. How did they both accomplish their challenging goals despite their unfair circumstances? Simple. They had the will.