Experimental Discovery, Data Models, and Mechanisms in Biology: An Example from Mendel’s Work - Mechanism and Causality in Biology and Economics - page 105

the paradigm of developmentalism, which dominated biological research in the
nineteenth century. Developmentalists do not separate the problem of heredity from
that of genesis and development. Therefore, developmentalism implies a concep-
tual framework of “soft heredity,” which makes no commitment to the idea of
particulate factors. 8 Only after developmentalism was replaced by the shift to the
new paradigm of hard heredity at the end of the nineteenth century were scientists,
at the beginning of the twentieth century, able to see the hereditary significance of
Mendel's experiment in a new light. Mendelian genetics was then built gradually,
because the rediscoverers, along with American geneticist Thomas Hunt Morgan's
team, reinterpreted Mendel's results based on the new conceptual framework of
hard heredity (Bowler 1989 : ch. 6). Let me call this alternative to textbook
orthodoxy the “paradigm-based account.”
If one carefully reads Mendel's paper, one finds that Mendel's original text is
more consistent with the paradigm-based account than with the orthodox view. In
the first and second paragraphs of the 1866 paper, Mendel clearly stated the
background and the goal of his experiment:
The striking regularity with which the same hybrid forms always reappeared whenever
fertilization between like species took place suggested further experiments whose task it
was to follow the development of hybrids in their progeny. (Mendel 1966 [1866], p. 1)
That no generally applicable law of the formation and development of hybrids has yet
been successfully formulated can hardly astonish anyone who is acquainted with the extent
of the task (Mendel 1966 [1866], p. 2)

...

If an experimenter's background and goal guide him to perform an experiment
and interpret its result, then certainly Mendel did not perform an experiment on
heredity, nor did he interpret the result from the perspective of genetics. In this
sense, Mendel did not discover the laws of heredity nor could he be regarded as the
founder of classical genetics. After the 1980s, some biologists and historians of
biology regarded Mendel as a hybridist, but still insisted that he fully realized the
hereditary significance of his experiments; he was therefore entitled to be called the
father of classical genetics (Mayr 1982 ; Hartl and Orel 1992 ). For instance, Mayr
argued that the strongest testimony in Mendel's paper is the word “Elemente”
(element), which Mendel postulated to account for the experimental result. Mayr
contended,

He postulated that the characters are represented by “gleichartige [identical] oder
differierende [differing] Elemente.” He does not specify what these “Elemente” are -
who could have done so in 1865? - but considers this concept sufficiently important that
he refers to these “Elemente” no less than ten times on pages 41 and 42 of the Versuche .
Evidently they correspond reasonably well to what we could now call genes. ( 1982 , p. 716)

8 “Soft heredity” means that transmission of characteristics to the offspring could be modified by
changes taking place in the parents' bodies due to new habits or a new environment. In contrast,
“hard heredity” rejects the notion of soft heredity and holds that characteristics are transmitted
unchanged from one generation to the next. See Bowler ( 1989 , p. 3).