Ladder, tree, web: The ages of biological understanding

Fundamental turns in biological understanding can be interpreted as replacements of deep models that organise the biological knowledge. Three deep models distinguished here are a holistic ladder model that sees all levels of nature being complete (from Aristotle to the 18th century), a modernist tree model that emphasises progress and evolution (from Enlightenment to the recent times), and a web model that evaluates diversity (since the 20th century). The turn from the tree model to the web model in biology includes (1) a transfer from modern to postmodern approaches, (2) a shift of semiotic threshold to the border of life, and (3) building the semiotic models of living systems, i.e., the rise of biosemiotics. The main issue of the 20th century has been the end of modernity. However, it has not yet been understood very well that this will also mean the end of the modern model of natural science. The modern age, as starting in the 17th century and being characterized particularly via the formation of experimental science together with the philosophy of Descartes and Bacon, would be replaced by anything that also replaces the experimental science, a strive for technological progress or innovation, and cartesianism. As John Deely (2001; 2004) has stated, this can be semiotics. Several analyses have shown that much of what has been called post-modern is more like late modern, or ultra-modern (Deely 2003: 22), which means that we still see the extension of modern era. This particularly seems to be true for the modernist science, the current situation of which demonstrates large fluctuations and extremist approaches. It is not an entire end of