To many, the idea of a God-designed universe seems at odds with the slow, chaotic processes described by evolution. How can we reconcile the notion of substantial being—the idea that things have real, essential natures—with the dynamic, ever-changing biological world? Let’s break this down with the help of analogies, examples, and the wisdom of both philosophy and science.
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1. What Is Substantial Being?
Think of a substantial being like a house built on solid ground. The house (a being) has its own essence—its "house-ness"—that makes it what it is. This essence is not the furniture (accidents) inside, which can change without altering the house’s nature. Similarly, in Thomistic philosophy, every being has an essence (what it is) and existence (that it is). These two combine to make a substantial being.
Analogy: Imagine a butterfly. Its colors, patterns, or even size may change (like rearranging the furniture), but its "butterfly-ness" remains constant. Evolution doesn’t erase the butterfly’s essence; it simply explains how butterflies might develop new traits over time.
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2. Evolution and Gradual Change
Evolution describes how life changes through processes like mutation and natural selection. For example, giraffes might have evolved long necks to reach higher foliage, a result of gradual adaptations over generations. This might seem like a rejection of fixed natures (substantial being), but in reality, it highlights how potentialities are actualized over time.
Philosophical Context: In Thomism, change is the realization of potential. A seed has the potential to become a tree, and evolution works similarly: living beings develop according to their inherent potentialities.
Scientific Example: The transition from reptiles to birds involved the gradual development of feathers and lighter bones. While these traits evolved, the reptiles and birds at each stage were still substantial beings with distinct essences—they weren’t blobs of matter waiting to become something meaningful.
Analogy: Think of baking bread. The dough transforms into bread through heat (change), but at every stage—dough, rising dough, baked bread—it has its own substantial identity.
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3. Substantial Being and Species
When a new species evolves, its substantial being corresponds to its new essence. Each individual organism maintains its own substantial being during its lifetime. When a population shifts significantly over generations, the essence of the species changes.
Analogy: Imagine a language like Latin evolving into French. At some point, the change is significant enough that we no longer call it Latin but French. Yet, Latin was always a real language, just as French is today.
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4. God as the Ultimate Cause
Thomas Aquinas teaches that God is the primary cause of all being, while evolutionary processes are secondary causes. These secondary causes (like mutation and selection) operate within God’s grand design, much like a writer using a pen to craft a story.
Analogy: Think of God as the author of a novel. The story unfolds dynamically, with twists and turns, yet every detail ultimately depends on the author. Evolution is one of the "plot devices" God uses to develop creation.
Philosophical Insight: Aquinas emphasizes that God doesn’t just set the universe in motion and step back. He continuously sustains creation, giving all things their being and purpose.
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Catholic Teaching on Evolution
The Catholic Church has embraced a harmony between faith and science, seeing evolution as a means through which God creates. Far from being at odds with belief in God, evolution reflects the creativity and wisdom of the divine.
1. What the Church Teaches
Pope Pius XII’s Humani Generis (1950): Evolution is acceptable as a scientific explanation of the body’s origin, provided it doesn’t deny the spiritual soul’s direct creation by God.
Pope St. John Paul II (1996): Evolution is "more than a hypothesis" and aligns with the Church’s teachings when seen as part of divine providence.
Pope Francis’s Laudato Si’ (2015): Evolution showcases the ongoing creative action of God in the natural world.
2. Human Dignity and the Soul
While our bodies may have evolved, the human soul is a direct creation of God. This reflects the Thomistic distinction between the material (body) and immaterial (soul).
Example: Picture a statue carved from marble. The marble represents the human body, shaped over time by natural processes. But the artist (God) imbues the statue with meaning and purpose—just as God gives each person a rational, spiritual soul.
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Vignette: A Thomistic View of Creation
Imagine a painter creating a masterpiece. At first, the canvas is blank (potentiality). The painter applies strokes, layer after layer, and the image slowly emerges. Evolution is like those layers—each stage is meaningful, contributing to the whole. For Thomists, substantial being is not erased by the process of creation but is made all the more beautiful by its unfolding complexity.
This analogy reflects the Catholic view: evolution is the unfolding of God’s creative act, with substantial being and essence grounding the reality of creatures at every step.
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References
1. Thomas Aquinas, Summa Theologica – A foundational text on metaphysics, causality, and the nature of being.
2. Pope Pius XII, Humani Generis – Encyclical addressing evolution and Catholic doctrine.
3. Pope St. John Paul II, Address to the Pontifical Academy of Sciences (1996) – On the compatibility of evolution and faith.
4. Pope Francis, Laudato Si’ (2015) – A reflection on creation and the relationship between faith and science.
5. Stephen Jay Gould, The Structure of Evolutionary Theory – A scientific perspective on the mechanisms of evolution.
6. Edward Feser, Aquinas – A modern introduction to Thomistic philosophy.