"If I look at the sky and see two identical airplanes, one following the other at a certain distance, my common sense, my cognitive make-up and my experience tell me that, putting aside the possibility of an optical illusion, I am indeed facing two distinct, albeit similar airplanes, rather than two instantiations of the same airplane occupying different chunks of space. One of the intriguing aspects of the copy theory of traces, especially as developed in this book, is that this basic informal principle of perception does not apply in the realm of language: under certain circumstances, the same linguistic object may occupy (be pronounced/perceived/interpreted) in two different sentential positions. There appears to be an analogue in the domain of general relativity theory: in the vicinity of an extremely massive body such as a black hole, the light emanating, say, from a star, may be bent in such a way that it goes through two distinct, opposite sides of the hole. Appropriately positioned, we might thus be able to see two instantiations of the same star. If the copy theory is correct, it will confirm in an intriguing way the fact that language has "properties that appear to be unusual in the biological world" (Chomsky, The Minimalist Program) but are instead rather close to those of physical systems of some complexity."

- Eduardo Raposo, University of California at Santa Barbara,

"Few ideas have gained such a central importance in modern linguistics as syntactic movement. This special property of human languages - which is in some way implemented in all theoretical models - is now at the very center of the debate within the Minimalist Programme for its major consequences on the general architecture of the language faculty. Norbert Corver and Jairo Nunes's anthology focus on the nature of this phenomenon providing strong original evidence in favour of the so-called "copy theory of movement" which constitutes one of the most innovative ideas of the Miminalist Programme itself. An unvaluable source of data and a thought-provoking challenge to any future research in the field."

- Andrea Moro,Università San Raffaele, Milan,