<i>The relation between many linguistic, or otherwise psychological observations is unclear, not even demonstrable. A proposal to formalize (a ‘generative grammar’) the subconscious observations discovered by Freud and their influence on human behavior is eventually possible</i>. <i>Freud has caused the greatest revolution in ages in Western thinking</i>. <i>He was certainly aware of this fact. ‘But’ he generously claims, ‘my work is scientific’</i>. <i>In this confusion of tongues, it may be wished that linguistics never become a science</i>. Balk-Smit Duyzentkunst (1974: 16) [translation mine] This introduction is meant to present the main theme of this book: the necessity of independent, objective demonstrations for linguistic analysis. It will compare and contrast different traditions in the demonstration of hypotheses within linguistics and try to define which kinds of demonstrations are considered to be independent and which are not. Finally, a short overview of the chapters will be given establishing their relationships to the general theme of the volume.