Ernst Haeckel’s ‘Kant Problem’: metaphysics, science, and art


Ernst Haeckel (1834–1919) has become famous, and perhaps infamous, for many reasons. Presently, he is probably most widely-known for his paintings of plants and animals in his very popular book, Art Forms in Nature, originally collected and published in 1904. However, in addition to Haeckel’s art, he is also well-known for his advocacy of Darwinism and Social Darwinism, for first coining the term ‘ecology,’ for having his work utilized by Nazi pseudo-scientists (Dombrowksi in Tech Commun Q 12:303–319, 2003), and for famously (perhaps fraudulently) producing drawings of animal and human embryos so as to confirm his biogenetic law (Gould in Nat Hist 109:44–45, 2000). Something Haeckel is not as well-known for today is the fact that he seemed to be both a strenuous critic of the metaphysical and moral philosophies of Immanuel Kant and yet also something of an adherent to Kant’s aesthetic views. In terms of metaphysics and morality, Haeckel sought to exorcise Kant’s ideas as much as possible from twentieth century views on science, humanity, and nature; however, in terms of aesthetic theory, Haeckel seemed to embrace a distinctly Kantian approach to art and artworks. This essay proposes to: (1) carefully examine Haeckel’s refutations of some of Kant’s central metaphysical concepts, (2) explore some of the, arguably Kantian, assumptions underlying Haeckel’s approach to aesthetics and his artistic practice, and (3) combine these two lines of inquiry into a portrait of Haeckel’s mind as one that is conflicted about the role Kantian philosophy, and more specifically Kantian noumena, should play in twentieth century science and art. This unresolved tension in Haeckel’s mind regarding Kant’s noumenal realm is what I propose to call his ‘Kant Problem’.

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  1. 1.

    This possible fraud and Haeckel’s famous dictum “Ontogeny recapitulates phylogeny” continues to be a controversial theme in recent creationism versus evolution debates.

  2. 2.

    I do not argue that Kant or Haeckel is necessarily correct/incorrect in any of their actual philosophical views, just that Haeckel’s arguments against Kant’s metaphysics are in significant tension with Haeckel’s seemingly Kantian assumptions about art, especially with regards to the intellectual ideas expressed by Haeckel’s artworks.

  3. 3.

    There are some serious questions brought up by this quote about whether Haeckel’s version of monism is in fact the monism of Spinoza as he says it is. It is particularly unclear whether Haeckel commits himself to any form of pantheism, which, if he does not, would make his view distinctly non-Spinozist. I am indebted to Jay Odenbaugh for this insight (among others) regarding the above discussion of monism.

  4. 4.

    Comments like these drove some Haeckel’s critics, like Erich Adickes in his polemic “Kant Contra Haeckel” (1901) to condemn Haeckel’s monism as a thinly veiled, and crass materialism.

  5. 5.

    In rough terms, Kant asserts that the categorical imperative is proved to be true a priori and tells us we should only act in ways that we could will to become universal laws of morality. If we are tempted to lie, Kant asks whether you could coherently believe that lying is a universally true law of morality; if not, then it is not a part of the categorical imperative, and thus it is our moral duty to never act in this way.

  6. 6.

    I refer here to Art Forms from the Ocean (2005), and Art Forms from the Abyss (2015).

  7. 7.

    After Haeckel, later in the twentieth century, the philosophical movement of Logical Positivism began to make similar claims about the uselessness, and literal meaninglessness, of metaphysics. See the excellent Cambridge Companion to Logical Empiricism for a deep discussion of the history and influence of this view (Rchardson and Uebel 2007). While it is clear that Haeckel began to see metaphysics as an obstacle to a thoroughly scientific worldview, it is unclear whether he thought that metaphysical claims were meaningless as the Positivists did.

  8. 8.

    Kant makes these claims in Critique of Pure Reason, but then later tried to explain them in a more accessible way in his Prolegomena To Any Future Metaphysics (1783/2001).

  9. 9.

    See especially §§IV–VI in Chapter II, Bk. II, Part I of Critique of Practical Reason (1788/1993) for these passages.

  10. 10.

    As mentioned above, Adickes’ main thesis in this work is to argue that Haeckel is in fact no monist at all, but is instead a straightforward scientific materialist.

  11. 11.

    I owe this insight to an anonymous referee for this journal.

  12. 12.

    This species is now called Cyanea annasethe. There are also two other species of jellyfish depicted in this plate.

  13. 13.

    I would refer to the whole of Chapter 2 from Richards’ book here as he does an excellent job of mapping out all of these influences on Haeckel there.

  14. 14.

    Haeckel’s interest in the symmetry and repeated structures of natural forms is especially apparent in his lifelong fascination with the Radiolaria, tiny ocean-borne unicellular organisms that create intricate silica-based skeletons around themselves. Haeckel documented thousands of different species of radiolaria over the course of his career. (See Artforms from the Ocean: The Radiolarian Atlas from 1862).

  15. 15.

    As examples of where Haeckel clearly artistically composed his pictures, many point to the plates depicting the higher animals, e.g., Plate 68 (frogs), Plate 79 (lizards), Plate 89 (turtles), and Plate 99 (hummingbirds), among others.

  16. 16.

    From my non-expert point of view, one clear example of an aesthetic embellishment in Art Forms in Nature is, I think, Plate 54 (squids and octopuses). The central squid’s tentacles are depicted as exceedingly long forming a lovely looping, filigree border at the top of the drawing. My zoological instincts, flawed they may be, tell me that those tentacles are not drawn to scale.

  17. 17.

    He uses Isaac Newton’s Philosophiae Naturalis Principia Mathematica as an example here, something Kant would view as a paradigmatic great work of science.


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The author would like to gratefully acknowledge the University of Montevallo for granting him sabbatical leave for the Fall 2017 semester. Thanks are also due to the Arteles Creative Center in Hämeenkyrö, Finland for an excellent winter residency during which much of this essay was written, as well as to Jay Odenbaugh and two anonymous reviewers for Biology and Philosophy for their assistance in improving this paper during the drafting process; all mistakes and shortcomings remain my own. Finally, many thanks to biologist Jill Wicknick, for helping with the proper usage of biological terms, and for first introducing the author to Haeckel’s magnificent paintings some 10 years ago.

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Correspondence to Stefan Forrester.

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Forrester, S. Ernst Haeckel’s ‘Kant Problem’: metaphysics, science, and art. Biol Philos 35, 27 (2020).

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  • Ernst Haeckel
  • Immanuel Kant
  • Aesthetics
  • Metaphysics
  • Art