It appears to be time to abandon realism (like cladistics)

Consistent conceptualization of reality offers only two fundamentally different approaches:

1. realism (ie, assuming that classes are real), and

2. nominalism (ie, assuming that objects are real).

The logical route of realism was fully explored first by the ancient Greek Parmenides, which led him to the conclusion that reality (coined as “what-is”) is one, change is impossible, and existence is timeless, uniform, necessary, and unchanging (from Wikipedia). The logical route of nominalism was entered, although not to explored to its end, by Heracleoitos, and continued to a possible end by Plato (in his ”Theory of forms”).

About 2,300 years after Plato, in 1901, realism was theoretically falsified by Bertrand Russell’s with his discovery that it ends in paradox (ie, Russell’s paradox), and about 30 years later it was also practically falsified by Einstein’s discovery that time is relative to the rate of movement on space (ie, speed). These discoveries thus also falsified Parmenides’ conclusion that change is impossible, instead supporting nominalism and its notion that change is not only possible, but moreover a fact.

Nominalism, and thus als oits hypothetico-deductive methodology (ie, falsification of hypoyheses), is the basis for traditional empirical science. The fact that this approach presently dominates scientific thinking is not a problem for sciences that are nominalistic by nature, like technology and most of the natural sciences, but it is for “sciences” that are realistic by nature, like biological systematics. The problem is how on earth we can test a realistic hypothesis that a particular organism IS of a certain class (like that I am a human)? Such questions are simply not scientific in the context of nominalism. They simply don’t have answers, because their answers are assumptions. The nominalistic answer to the realistic question of which class an organism belongs to is “the class we say it belongs to”. An organism IS of a certain class simply if we say that it IS of this class. Which class an organism IS of is thus not something we can find out, but something we decide. Realistic questions simply do not have objective answers, but instead ask for the bases for the assumptions that the questions rest on. As such, they may also have the answer: none. An organism IS not necesarily of any class. It may be classless.

Due to its realistic nature, biological systematics has always been torned between realism and nominalism. The discipline itself pushes its practitioners towards realism by its focus on typology and thereby classes, but it also contains a counteracting force of a minority trying to adhere to nominalism and its methods of traditional empirical science. From about the 1400-th century and till about 1950 it was dominated by nominalists, reaching its height with the Linnean systematics, but from the 1960-ies, realists have regained dominance by the realistic idea of the Nazi entomologist Willi Hennig that there is indeed a “true tree of life”, although this idea thus was shown to be paradoxically contradictory by Bertrand Russell about 60 years before Hennig put forward this idea. The idea was thus falsified long before Hennig presented it. It means that biological systematists are presently searching for what Bertrand Russell demonstrated is a paradox about a century ago, that is, the ”true tree of life”.

Hennig claimed that it is time to accept the idea “a true tree of life”, but it rather appears to be time to abandon the platform Hennig rested on when he expressed this claim, that is, realism. The problem is actually not which “the true tree of life” is, but that there isn’t any “true tre of life”.

Another contribution to understanding of conceptualization http://menvall.wordpress.com/