Destructive Interference: The Evolution of "Lamarckism"

Table of Contents

I. INTRODUCTION

II. HISTORICAL OVERVIEW

III. STRICT LAMARCKISM: THE INFLUENCE OF CIRCUMSTANCES AND THE FOUR EVOLUTIONARY LAWS

IV. THE EVOLUTION OF “LAMARCKISM”

V. MODERN LAMARCKIAN CLAIMS IN PERSPECTIVE

VI. CONCLUSION

BIBLIOGRAPHY

Destructive Interference: the Evolution of “Lamarckism”

“ Nature, in producing successively all the species of animals, beginning with the most imperfect or most simple in order to end her work with the most perfect, has gradually made their organization more complex; and with these animals spreading generally throughout all the habitable regions of the globe, each species received from the influence of the circumstances in which it is found the habits now recognized in it and the modifications of its parts that observation shows to us…”

-Lamarck, Philosophie Zoologique, 1809

I. INTRODUCTION

Most biologists resist positive claims about Lamarckian modes of inheritance, as they perceive such claims as threatening the hegemony of the Darwinian paradigm in which they operate. However, this hesitance may be misguided and unconstructive, should it arise from misconceptions about the relationship between contemporary ‘Lamarckian’ discoveries and the views which Lamarck himself actually held. Given the recent revitalization of interest in Lamarckian evolutionary perspectives (Cairns et al.

1988, Hall 1991, Ewer 1996, 2004; Steele 1979, 1998; Jablonka and Lamb 2007), and the lingering ambiguity concerning what constitutes Lamarckian theses, it would be prudent to evaluate the relationship between contemporary Lamarckian theses and traditional Lamarckian positions.

Scientists working in evolutionary fields tend to label as ‘Lamarckian’ any claims that imply the inheritance of somatic mutations; adaptations derived through interaction between the organism and environment, and subsequently passed to offspring (the most famous example being the giraffe stretching its legs and neck to reach higher leaves).

However, the relationship connecting contemporary ‘Neo-Lamarckian’ ideas and traditional Lamarckian ideas is dubious at best, and conceptually misleading at worst, both for working scientists and casual laymen. For example, traditional Lamarckian inheritance acts through the whole organism or its parts, while modern Lamarckian inheritance tends to act on individual cells or even whole populations. The invocation of the label “Lamarckian” carries historical and conceptual baggage that I would like to disambiguate from recent, supposedly ‘Lamarckian’ modes of inheritance. To accomplish this, I will reveal and clarify the evolutionary claims that Lamarck himself published, most notably in Jean-Batiste Lamarck’s Philosophie Zoologique, and evaluate the relationship between his traditional claims, and more recent claims labeled as “Lamarckian” by contemporary scientists. This paper will provide an analysis of the conceptual interplay occurring between modern Lamarckian claims, and what Lamarck actually believed and published, via an investigation of the evolution of the term Lamarckian/Lamarckism from 1809 to the present; my conclusion, then, should be a fair appraisal of the relationship existing between Lamarck’s actual claims and contemporary Neo-Lamarckian claims.

II. HISTORICAL OVERVIEW

By 1815, Jean-Baptiste Lamarck had articulated what he believed to be “a truly general theory, linked everywhere in its parts, always consistent in its principles, and applicable to all the known data.” This truly general theory was nothing less than the union of a wealth of empirical observations of the natural world and a guiding philosophy of life that accounted for “the source of existence, the manner of being, the faculties, the variations, and the phenomena of organization of the different animals.” (ZP 184) Though Lamarck had established himself as a master systematist rivaling Linnaeus among his own contemporaries, he considered his work in nascent biology and evolution (incidentally, Lamarck actually coined the term ‘biology’) to be his most difficult, ambitious, and ultimately, his most important contribution to human understanding (Lamarck 1809). However, Lamarck’s general theory was almost universally ignored (Corsi 207); at best, he faced polite indifference, and at worst, outright slander and ridicule (Madaule 13). From the very outset of its publication, Lamarck’s Zoological Philosophy was repeatedly misinterpreted, his ideas misquoted, and his name misappropriated. Unfortunately, the distortion of his ideas did not cease upon Lamarck’s death; even his academic eulogy, tragically written by his adversary Georges Cuvier, served to confuse and malign Lamarck’s ideas on the evolution and organization of nature (Cannon 1959). In the following sections I will provide the historical context from which Lamarck’s general theory of biology arose, with special attention paid to the ways in which the scientific environment distorted his ideas. These observations will be informative when I review the ‘evolution’ of Lamarckism in the history of science and attempt to make sense of the connection between historical Lamarckism and modern Lamarckian claims.

Lamarck was inspired by the successes of Newton in providing a unified scientific account of the motion of heavenly bodies and earthly motion in general; he hoped to find similar success in accounting for the complexity of all biological life. In grand fashion, he hoped to find and describe nature’s plan (Glass 1959). Particularly, Lamarck stressed that there is an obvious trend of increasing complexity among living things, and that this complexity was derived over time during the history of life. Just like the laws governing the motion of planets and stars, Lamarck assumed that there must be properties and plans that guided, and continue to guide, the evolution of life-forms, resulting in the natural and fine gradations observed by himself and others of his time (Jordanova 1984). He was perhaps no less influenced by social, political and economic theories than by his own observations of the natural world. For example, Lamarck was known to take frequent walks with Jean-Jacques Rousseau, and in various letters it is apparent that he applied some of Rousseau’s political philosophy to the natural world (and vice-versa, to be fair) (Madaule 1982). From the ideological French climate and his observations of the natural world, Lamarck developed a two-factor approach to successive biological change, consisting of 1) the natural inherent progress of organic development and 2) the modification of this progress by constraining external circumstances (Burkhardt 1977).

By 1809 in his Zoological Philosophy, Lamarck explicitly denotes the natural progress of evolution directed by nature and the distorting and random effects of accidental circumstances (the environment): “The state in which we now see animals is on the one hand the product of the increasing composition of the organization, which tends to form a regular gradation, and on the other hand that of the influences of a multitude of very different circumstances that continually tend to destroy the regularity, the gradation of the increasing composition of organization. “ (Lamarck 1809; not my emphasis)

These remarks indicate the general constructive conflict occurring between directed adaptation by populations over long periods of time, and sudden and accidental changes among populations resulting from environmental alterations, leading to the irregularities found upon close inspection of Lamarck’s series of living things. Lamarck, it must be noted, had not restricted his professional analyses to living matter; he published widely on geological and marine history as well (Bowler, 1989). From his observations in geology, he recognized that the earth, though having undergone gradual and sometimes sudden changes over its long history, had not become, qua environment, more complex. Thus, he reasoned, nature itself must tend toward the more complex via inherent guiding properties. It were these inherent properties, common to the cells of all living things, that resulted in the gradation of living things on the planet, and it was the intervening circumstances of environmental change that caused irregularities among the more uniform gradations observed in nature (Lamarck 1809). So, Lamarck’s philosophy stands somewhat elegantly between the extreme teleological views espoused by the ancients (Aristotle, Democritus, &c), and the absolute randomly generated evolution espoused by neo-Darwinians holding sway in modern times.

Another important tenet of Lamark’s thought involved the subordination of certain biological features in relation to others (Burkhardt 1977).

[...]