What is truth? Is every statement either true or false? Do we know anything? What can we know in philosophy? For example, what are our moral obligations? Do we have a free will? And does God exist? This book uses arguments, thought experiments and formal logic to answer these questions. Most parts of the book should be easy to understand. However, some basic knowledge in theoretical philosophy and logic may be useful to understand some of the details. Omar A. Ayaita, born 1987, studied philosophy in Tubingen, Konstanz (both Germany) and Amherst, Massachusetts (USA).