Last Words on Evolution: A Popular Retrospect and Summary

In Short

This book serves as both a retrospective on the nineteenth-century battle for the theory of evolution and a vigorous manifesto for the Monistic philosophy. Drawing on paleontology, comparative anatomy, and embryology, the author argues that man is inextricably linked to the animal kingdom through descent from extinct anthropoid apes. By detailing the development of the human organism from a simple cell, the work positions evolution as an objective reality that renders supernatural creation myths obsolete, while critiquing the strategic attempts by religious institutions to reconcile their dogmas with established natural laws.

The Story

The narrative begins with a panoramic view of the nineteenth-century scientific landscape, where the idea of evolution transitioned from a fringe hypothesis to a bedrock of modern knowledge. The author situates this shift against the backdrop of earlier thinkers like Lamarck and the influential "cell theory" of Matthias Schleiden, which provided the mechanical basis for understanding how complex organisms develop from a single ovum. The story arc follows the progression from the inorganic laws of physics, already accepted by the scientific community, to the organic realm, where the resistance of theologians and conservative academics remained fierce for decades.

As the account progresses, the focus sharpens on the specific conflict regarding human lineage. The author recounts his own early efforts to map the genealogical tree of vertebrates, emphasizing that the human frame is fundamentally identical to that of other mammals. This creates a central point of tension: the "privileged position" of man, which traditional institutions and the German Anthropological Society—led by Rudolf Virchow—sought to defend by dismissing evolutionary evidence as mere speculation. The author frames this resistance not as scientific disagreement, but as an act of vanity, comparing it to the pretensions of the aristocracy who fear the democratization of knowledge.

The narrative reaches its critical turning point with the emergence of "ecclesiastical evolution," a strategy employed by Jesuit writers like Erich Wasmann. These figures, attempting to preserve the Church’s relevance, began to publicly accept biological evolution while simultaneously carving out a divine exemption for the human soul. The author views this as a dishonest "change of front" and a form of sophistry, arguing that the psychological and mental life of man is, like his anatomy, governed by natural and physical laws. He concludes that the persistence of belief in immortality or free will is not a product of spiritual truth, but a relic of political and social tradition designed to maintain the power of the altar and the throne. The work ends with an urgent call for the complete replacement of blind faith with rational science, viewing the current clerical reaction in Germany as a temporary, albeit dangerous, anachronism that must eventually yield to the progress of enlightened inquiry.

How It Unfolds

The rise of evolutionary thought The opening section establishes the historical struggle to ground biology in observable law, moving from ancient myths to the empirical rigor of the nineteenth century. It emphasizes the foundational role of the cell and the embryological discoveries that link human development directly to the animal kingdom.

The anatomy of heritage The narrative examines the physical evidence that connects humans to primates, dismantling the "gulf" that many contemporaries attempted to invent between man and beast. The author highlights the consistency of vertebrate structure as the primary witness to our common ancestral tree.

The defensive maneuvers of dogma The middle chapters analyze the intellectual shift in religious circles, where clergy members began to accept biological facts only to reinterpret them through the lens of metaphysics. This section dissects the specific arguments used by Jesuit writers to protect the concept of a divine soul from the reach of biological causality.

The finality of natural law The concluding portions address the "soul" and "free will," arguing that these, too, are subject to measurable physical processes. The author challenges the reader to embrace a Monistic worldview, where the unity of nature leaves no room for supernatural intervention, and asserts that the future belongs to secular, scientific education.

The People

The book is driven by the author, Ernst Haeckel, who stands as the primary advocate for a strictly naturalistic and Monistic explanation of life. He positions himself as a defender of "truth-seeking" against the obfuscation of the clergy. Opposite him, he places Father Erich Wasmann, an entomologist whose attempts to bridge Catholicism and Darwinism serve as the primary target of Haeckel’s critique. Wasmann represents the institutional attempt to save the "divine image" of man by bifurcating human nature into the biological and the spiritual. Rudolf Virchow appears as the significant academic antagonist whose immense authority as a pathologist and institutional leader long stifled the spread of evolutionary teaching in German schools. The reader also encounters historical figures like Johannes Müller, whom Haeckel treats with profound respect as a "great master" of biology, and Lamarck, the pioneer who first dared to suggest the transformation of species.

In Its Own Voice

The intimate connection that was proved to exist between all branches of knowledge, once the continuity of historical development was realised, and the union of them all through the Monistic philosophy, are achievements of the last few decades.

(The author summarizes the intellectual progress made by the end of the 19th century.)

Even the human organism is at first a simple nucleated globule of plasm, about 1/125 inch in diameter, barely visible to the naked eye as a tiny point.

(The author explains the material, biological starting point of every individual.)

It is clear that the Jesuit writer lacks competence in this department; that he has only a superficial and inadequate acquaintance with comparative anatomy and embryology.

(The author critiques the scientific standing of his theological opponents.)

What It's Really About

The central argument is that the theory of evolution is not merely a biological fact, but the necessary cornerstone of a broader, secular philosophy. The book grapples with the question of whether human consciousness and morality can exist within a purely material world, or if they require a metaphysical explanation. By rejecting the dualism that separates the "animal body" from the "divine soul," the author forces the reader to confront the implication that man is a product of natural history rather than an act of special creation. The work is fundamentally about the power of science to displace traditional authority, asserting that the "unity of nature" is a totalizing truth that must eventually govern ethics, law, and education.

Why Read It Today

Readers interested in the history of science or the evolution of the conflict between faith and rationality will find this book a bracing, primary-source experience. It is a polemic, written in the direct, uncompromising tone of a man who spent his life in the trenches of a cultural war. You will feel the heat of the Victorian-era debates, as well as the author’s sharp, often caustic disdain for the institutional powers of his day.

The book is not a modern scientific manual; it is a historical artifact that reflects the specific fervor of early 20th-century German intellectual life. A reader must be prepared for the author's intense, often abrasive style, which does not shy away from political attacks on the Church or the German government. While the specific scientific debates—such as the classification of the primates—have been vastly expanded by modern genetics, the clarity of the author’s philosophical position remains striking. It is a demanding read that challenges the reader to decide between a supernatural worldview and one rooted entirely in the material evidence of the natural world. Those who value conviction, historical perspective, and a clear, unwavering argument will find much to engage with here.