On why-questions in physics

In natural sciences, the most interesting and relevant questions are the so-called why-questions. There are several different approaches to why-questions and explanations in the literature, however, most of the literature deals with why-questions about particular events, such as ``Why did Adam eat the apple?''. Even the best known theory of explanation, Hempel's covering law model, is designed for explaining particular events. Here we only deal with purely theoretical why-questions about general phenomena of physics, for instance ``Why can no observer move faster than light?'' or ``Why are Kepler's laws valid?''. Here we are not going to develop a whole new theory of why-questions in physics. We will just touch upon some ideas and examples relevant to our subject.