In this text, we will examine an important assumption: Thinking well matters and whatever matters to us is better lived, if we think well about it. What does it mean to think well? We need to inquire into the meaning, applications, and worth of critical thinking. To understand critical thinking, it is important to notice that how we will inquire in this text will itself exemplify critical thinking. If you appreciate Epictetus" sensitivity to the value of our minds, you will take notice when I am not practicing critical thinking and always when it matters, think critically for yourself.