Puzzles for ZFEL, McShea and Brandon’s zero force evolutionary law

Abstract

In their 2010 book, Biology's First Law, D. McShea and R. Brandon present a principle that they call ''ZFEL,'' the zero force evolutionary law. ZFEL says (roughly) that when there are no evolutionary forces acting on a population, the population's complexity (i.e., how diverse its member organisms are) will increase.Here we develop criticisms of ZFEL and describe a different law of evolution; it says that diversity and complexity do not change when there are no evolutionary causes.

Toy models for macroevolutionary patterns and trends

“…Unless evolutionary forces (e.g., strong selection or genetic drift) intervene, complexity will generally increase over time. Barrett et al (Barrett et al, 2012) suggest that the ZFEL should be inverted, but still agree with the notion of increasing complexity given the proper conditions. We have shown here some examples of how toy models can capture general trends and perhaps even progressive evolution without the biases of a single dataset or the strictures of a formal theory.…”

Explanation and the Evolutionary First Law(s)

“…But as Barrett et al (2012) point out, laws may be limited in scope without losing their nomological status. More importantly, the HW principle answers for one class of organisms a question that is of general relevance: what is the effect of reproduction alone on the genetic makeup of a population?…”

“…The contest between different interpretations of the first law provides a useful opportunity to clarify the structure of explanations based on it and to identify their inherent strengths and limitations. 2 Biology's First Law has generated a great deal of lively discussion among philosophers both in person (e.g., Brandon 2010b;Erwin 2011;Huang 2011;Turner 2011) and in print (e.g., Barrett et al 2012;Brandon and McShea 2012). Much of this conversation has centered on the coherence of the ZFEL and its supporting conceptual apparatus, as well as its claim to lawhood.…”

“…Though the ZFEL and the HW principle are not the only first laws articulated in the literature, they exemplify the two basic explanatory strategies proposed so far. Like the ZFEL, the principle of drift (PD) offered in Brandon (2006) describes a state of evolutionary change, while the zero-cause evolutionary law (ZCEL) suggested by Barrett et al (2012) follows the HW principle in specifying the conditions under which a population will experience stasis. of evolutionary explanations are required by various categories of biological phenomena.…”

“…Of the three resulting readings of the HW principle, only one is charged with falsehood, while the others are simply deemed misleading. But as Barrett et al (2012) point out, H-W 1 and H-W 2 are logically equivalent, and the reply by Brandon and McShea (2012) drops the bifurcation of the principle. Here I respond to a core argument that appears in both publications.…”