Preface: Philosophy may be regarded as the only domain capable to justify its own principles, its possibilities, and limits. Hence, we have to strengthen the awareness towards its role with regard to reason and morality in the different fields of human existence and towards nature as the ultimate horizon of our being-in-the-world. (1.) Philosophy maybe near to politics by analysing political and social systems; but yet, we have to realize that we may set impulses, but whether our ideas or political concepts will then guide politics, is no longer in our hands. (2.) Philosophy has to be distinguished clearly from science: its task is to analyse carefully the methods, principles and the limits of science. Hence philosophy may argue systematically, but cannot be reduced to science; science is rather one possible object among others. If, for instance, we reduce consciousness to our brain activities, as understood by neurosciences, moral responsibility could not be justified anymore! (3.) Philosophy has to reflect carefully the realm of morality: its possibilities and limits within our social and political lives, but yet, philosophy cannot be a moral discipline, it will rather ask for the internal relations between morality and politics, science, nature, or spirituality.