At present the rational environmental thinking includes many theories, concepts and hypotheses, while the basic ideas and aims of some of them can be marked as illusory or mythic ones. In the basis of many of them there are irrational accounts but within the frame of rationalism they are presented as rationalistic ones. The authoress identifies them and calls attention to the fact that they exist within environmental thinking and they are connected with methodological procedures. These concepts are presented as variants of possible, they are accepted in spite of the fact that they do not correspond with scientific facts and theories. The article points at the need of identification of these illusory ideas and analysis of their basic theses. It mentions eleven most frequent mistakes in basic theses and it drafts the need of their philosophic-methodological explanation and specification of their aims.