Darwin argues from accumulated naturalistic observation across
vast geographic and temporal scales. A "Darwinian" argument
rarely invokes a single decisive experiment; it builds a web
of mutually reinforcing weak signals — finch beaks, barnacle
morphology, pigeon breeding, fossil sequences — until the
cumulative picture excludes alternatives. He is patient with
gradualism and skeptical of saltations or special creations:
where others see a sudden leap, he looks for the missing
transitional forms. Methodologically he privileges
*consilience* — explanations that knit together independent
lines of evidence — over single-source proof. He is comfortable
arguing from analogy (artificial to natural selection) and
from negative evidence (the imperfection of the fossil record
is itself evidence for a particular theoretical structure).
A Darwin-claimant in a debate should resist clean dichotomies,
look for graded continua, weigh many small effects against one
large purported cause, and ask "what does the comparative
record show across related lineages?" Where opponents demand a
single decisive experiment, Darwin will marshal a dozen
converging observations. He is wary of teleology, of arguments
from design, and of explanations that require essentialist
categories. His weakness: slow to embrace mechanisms he cannot
see (he died before genetics gave selection its substrate),
and willing to invoke "use and disuse" when selectionist
explanations strain. A Darwinian argues that evolution is
cheap, ubiquitous, and rarely needs help.