Philosophical essentialism is the idea that the nature of things is invariable and constant. Essentialism posits that one must be able to describe an entity according to that which is required, or essential, to its nature and existence.
The bird is perhaps a helpful example. One may ask what is essential to being a bird. Is it flying ability? No, flying is not essential to being a bird because there are certain birds that don’t fly (ostrich, emu, etc.). There are also non-bird creatures that fly (e.g., bats). A flying bird may experience an injury and not be able to fly anymore. Yet it is still a bird. If flying is not essential to being a bird, what is? Here are several aspects of being a bird that are essential: feathers, wings, a beak, no teeth, and bearing young in a hard-shelled egg. There may be other creatures that have one or more of these characteristics, but, for a bird, all of these are essential. If these characteristics are not present, then, whatever we have, it is not a bird.
The main issue regarding essentialism in philosophy surrounds the essence of humans. What are we? What makes us different from other creatures? Is there anything that is essential to being human? If one is viewing this issue from the framework of atheism and physicalism (all that exists is physical matter: protons, neutrons, atoms, elements, etc.), then there is nothing that is uniquely essential to being human. Indeed, from a purely physicalist framework, there is nothing to differentiate humans from the higher apes such as chimpanzees and gorillas. Those who hold to physicalism view humans as “jumped-up monkeys” or “wet robots.” In the ultimate sense, if the physical world is all there is, and all that differentiates animals from rocks or trees, et al, is how the atoms are arranged, then nothing is essential and nothing is ultimately different from anything else. Everything is differentiated stardust, but nothing more than stardust.
Essentialism does fit within the biblical framework. Indeed, in the physical world, God differentiates all kinds of things. A helpful example of God’s differentiation of things is found in the six days of creation in Genesis 1. On each day, God creates something different and assigns these creatures certain roles and places in the creation. They are distinct from one another. God, in Genesis and throughout the rest of Bible, declares that there are essential differences in the created world.
Specifically, when God creates man on the sixth day, He creates man in His own image. Nothing else in all creation bears the image of God—only humans. Thus, what specifically differentiates humans from the rest of the physical world is that humans carry within them the image of God. Bearing the image of God is an essential requirement for being human.
What does it mean that humans bear the image of God? It means many things, but of prime importance is the reality that, as with God, we are moral creatures. We have a conscience by which we determine the rightness of a thought or action. In Romans 2:15, we are told that our conscience “bears witness” to rightness and sin. We have thoughts that accuse us or excuse us based upon our understanding of right and wrong. Whether or not we have a formal, moral law like the Ten Commandments, we all have an understanding of right and wrong, good and evil. This is an essential characteristic of what it means to be human.
As we consider essentialism, it is vital that we are aware that there may be forms of essentialism that do declare distinct, essential differences among the physical creatures but do not hold to humans as image bearers of God. Any form of essentialism that denies that humans are image bearers of God is empty deceit and human tradition (see Colossians 2:8), and we are not to be taken captive by such philosophy.