 In face of expanding researches, the unifying emphasis on organization, classification and foundation led to exploring differences and rationalizing boundaries. The German intellectual current culminated in the late nineteenth century in the debates among philosophers such as Windelband, Rickert and Dilthey. In their views and those of similar thinkers, a worldview often included elements of evaluation and life meaning.  Kant had established the basis for the famous distinction between the natural sciences (Naturwissenschaften) and the cultural, or social, sciences (Geisteswissesnschaften) popularized in theory of science by Wilhelm Dilthey and Wilhelm Windelband. Dilthey, Windelband, his student Heinrich Rickert and Max Weber (although the first two preferred Kulturwissenschaften, which excluded psychology) debated over how differences in subject matter between the two kinds of sciences forced a distinctive difference between their respective methods. Their preoccupation with the historical dimension of the human phenomena, along with the Kantian emphasis on the conceptual basis of knowledge, led to the suggestion that the natural sciences aimed at generalizations about abstract types and properties, whereas the human sciences studied concrete individuals and complexes. The human case suggested a different approach based on valuation and personal understanding (Weber’s verstehen). For Rickert, individualized concept formation secured knowledge of historical individuals by establishing connections to recognized values (rather than personal valuations). In biology, Ernst Haeckel defended a monistic worldview (Richards 2008).