What has homo sapiens really bought at the cost of schizophrenia? Evolutionism seen through a philosophy of language

One of the most intriguing positions in the evolution debate is that schizophrenia is the price that Homo sapiens pays for language. Language and schizophrenia are both unique traits of the human species and are equally distributed around the world. Crow (Crow, 1996, 2000) (Kim, 2000) proposed a common origin, back in a genetic mutation able to alter the anatomical and functional hemispheric balance, fixed in the sexual X chromosome about 100,000 years ago. Several facts support his thesis: the distribution of handedness among the normal and the psychotic population (Gur, 1977), the dating of the supralaryngeal vocal tract specialization (Lieberman, 1975, 1991), and the finding of FOXP2 as a putative genetic correlate (Enard et al., 2002). However, there are two drawbacks to Crow's theory, one concerning the evolution history and another the linguistic characterization of schizophrenia. On the first point, while schizophrenia and language are human specific, lateralization is not; on the contrary it is widespread among current species and through paleontological ages (Rogers and Andrew, 2002). Concerning the second point, the linguistic deficits connected to schizophrenia are highly arguable. If the schizophrenic patient were really deprived of the hemispheric specialized processes, his linguistic performances - especially syntax - should suffer as a result. This is not the case. Linguistic studies (Irigaray,1985)(Pennisi, 1998), have shown that some schizophrenic patients even exhibit enhanced syntactic capabilities. They not only preserve normal articulatory performances but are especially able in morphological constructions (neologisms and paralogisms built on formally correct monemes) and discourse constructions (oral and verbal fluency, precise syntactic linkage and ordering). Thanks to such abilities, they can build complete "neolanguages". Extended linguistic analysis reveals that even verbigerations retain organization of meaning intact. So, what is the specific language pathology of schizophrenia? As Crow himself noted (Crow,2000), the original traits of schizophrenia are a) internal voices; b) the theft of thought, and c) the escape of ideas. All seems to depend on a lost identification of the linguistic self. In other words, defects seem to seat at the upper cognitive level responsible for the self-identification mechanisms, showing, when corrupted by schizophrenia, a "loss of natural evidence" (Blankenburg, 1998). Several EPR studies support this view (Rockstroh, 2001). Therefore the schizophrenic deficit seems to be a weakness in the ontological rooting of language in reality more than a defect in its formal mechanics. If this is the case, Crow's slogan can be rephrased as: "Schizophrenia is the price that Homo sapiens pays for the capability of language to generate existential semantics". And not for articulatory and syntactic capabilities. Still believing in a common root for language and schizophrenia, lateralization and the emergence of a linguistic consciousness now appear far too distant for an explanation. Too distant in time, from the origin of the brain hemispheric specialization to the evolution of a language-centered form of life. But too distant in ontogenesis as well, from the sole biological inheritance to the fundamental role of the cultural environment in the emergence of language functionality. Janet's "fonction du réel" (Janet, 1903), can only emerge from the binding between the natural and the historical aspects of language, something which is missing from schizophrenic language.