American linguistics in the 20th century witnessed two totally opposite but equally powerful lines of thought: the former was represented by the mentalist direction in anthropological linguistics, initiated by Franz Boas and carried on by Edward Sapir and Benjamin Lee Whorf, while the latter was Leonard Bloomfield's structuralism. Mentalist descriptivists considered that the language of a people could only be studied in close connection to the culture of that specific people, because their language structures reflected the speakers' mentality (or particular way of seeing the world), influencing it, at the same time, by transfer of linguistic norms into the domain of experience. At the opposite pole, structuralist linguists (Bloomfield, Zellig Harris, Noam Chomsky), despised any reference of language analysis to mental processes, since they strongly believed this approach was highly unscientific, and made a purpose for themselves to completely ignore meaning.Leonard Bloomfield is considered to have been for American linguistics what de Saussure was, in his time, for the European one. He set out to take a fully scientific, empirical approach to language, which meant exclusively direct observation of visible phenomena. He thought variability in human behavior was due solely to the complexity of the human organism, especially that of the human nervous system. In this line of thought, any of man's activities could be described in purely scientific terms. For example, a word like salt can be described very accurately because we can give it a scientific definition: NaCl or sodium chloride. In contrast, words like love or hate cannot be defined yet, since we lack the necessary knowledge at present, but the future might change that.As for human language in its totality, Bloomfield considered it to be a system of conditioned reflexes triggered by verbal stimuli. This is how he explains the act of speech: a speaker produces a noise (stimulus) that triggers a reaction (response) in the nervous system of the interlocutor (receptor). Any reference to ideas is left out in the description, because Nonlinguists /.../ constantly forget that a speaker is making noise, and credit him, instead, with the possession of impalpable. It remains for the linguist to show, in detail, that the speaker has no and that the noise is sufficient [1].Judging things from a wider perspective, we notice that American structuralism is well impregnated with behaviorist values. Indeed, the psychology of the same early 20th century was dominated by behaviorists. In Russia, the principles of classical conditioning had been firmly established by Ivan Pavlov and his experiments that demonstrated how an originally neutral stimulus (a sound), if repeatedly associated with a reflex (salivation before food), induced a reflex response. In the U.S.A., psychologists like John Watson and B. F. Skinner founded their research on the direct observation of animal behavior, ruling out any reference to concepts like mind or psychic phenomena. Any behavior originated in learning to associate a stimulus and a response.The fundamental laws of learning were extracted from this type of study, but they were applied on man as well. This is a very bizarre extrapolation from the mechanic nature of animal kingdom activities to the infinite complexity of human activities. Speech, for example, displays features of utmost sophistication, yet all behaviorists could see in it just another type of behavior (called verbal behavior) that could be accounted for in (the same) terms of stimulusresponse.We can now parallel the two phenomena described so far: on the one hand, psychologists trying to formulate a psychological theory without any reference to the central concept of mind, and, on the other hand, linguists trying to formulate a language theory without any reference to the central concept of meaning. Since meaning lies in the mind of the speaker, everything becomes clearer if we detect the fundamental idea that overwhelmingly influenced the scientific thinking of that time: Darwin's hypothesis on evolution. …