More specifically courage is the ability to recognise your fear, understand what is scaring you, comprehend why it is and then blindly ignore it and do it anyway.
Doing it anyway is the application of rationality with a healthy acceptance of what will be will be, over what is stopping you. Society has developed because of this: What’s over this hill? What does this taste like? What happens if I do this? It is sanitised out of us now and we are poorer for it.
So if you are fighting your Cancer battle again this weekend, or Sky Diving or just living your life, keep being brave, keep making the tough decisions, make those choices and ask the questions you might not like the answer to.
The world needs more brave souls.