Paleolinguistics is a term used by some linguists for the study of the distant human past by linguistic means. For most historical linguists there is no separate field of paleolinguistics. Those who use the term are generally advocates of hypotheses not generally accepted by mainstream historical linguists, a group colloquially referred to as "long-rangers". Background The controversial hypotheses in question fall into two categories. Some of them involve the application of standard historical linguistic methodology in ways that raise doubts as to the validity of the hypothesis. A good example of this sort is the Moscow school of Nostraticists, founded by Vladislav Illich-Svitych and including Aharon Dolgopolsky, Sergei Starostin, and Vitaly Shevoroshkin, who have argued for the existence of Nostratic, a language family including the Indo-European, Afro-Asiatic, Altaic, Dravidian, and Kartvelian language families and sometimes other languages. They have established regular phonological correspondences, observed morphological similarities, and reconstructed a proto-language in accordance with the accepted methodology. Nostratic is not generally accepted, in part because critics have doubts about the accuracy of the correspondences and reconstruction. Other hypotheses are controversial because the methods used to support them are considered by mainstream historical linguists to be invalid in principle. Into that category fall proposals based on mass comparison, a technique in which relationships are postulated on basis of sets of words resembling each other in sound and meaning, without establishing phonological correspondences or carrying out a reconstruction. Prominent examples are the work of Joseph Greenberg and Merritt Ruhlen. Most linguists reject that method as unable to distinguish similarities from common ancestry from those from borrowing or chance. Paleolinguists Other linguists who may be considered paleolinguists due to their advocacy of long-range hypotheses include: John Bengtson, Knut Bergsland, Derek Bickerton, Václav Blažek, Robert Caldwell, Matthias Castrén, Björn Collinder, Albert Cuny, Igor Diakonov, Vladimir Dybo, Harold Fleming, Eugene Helimski, Otto Jespersen, Frederik Kortlandt, Samuel E. Martin, Roy Andrew Miller, Hermann Möller, Susumu Ōno, Holger Pedersen, Alexis Manaster Ramer, G.J. Ramstedt, Rasmus Rask, Jochem Schindler, Wilhelm Schmidt, Georgiy Starostin, Morris Swadesh, Henry Sweet, Vilhelm Thomsen, Vladimir N. Toporov, Alfredo Trombetti, and C.C. Uhlenbeck. An entirely different point of view underlies Mario Alinei's Paleolithic continuity theory, which is based on the doctrine of polygenism rather than that of monogenesis. Applications Many recent interdisciplinary research papers use paleolinguistics as one of their approaches. For example, evolutionary biologist Mark Pagel has written an article titled Ultraconserved words point