The question of purpose or why things are as they are and what they ought to be began mainly with Plato and Aristotle in Western history. For Plato, purpose was woven into the fabric of reality. Every object, every living thing, every human being ultimately pointed to a higher Form, an ideal. Beauty, justice, goodness. Purpose was sublime, residing in the heavens. The world we could see was merely its flawed reflection. Aristotle turned this vision upside down. Purpose (telos) was not in the heavens, but in the nature of objects, according to him. An acorn became an oak tree because its telos was internal. Its form was its destiny. Aristotle's universe was a place where change was not random but the result of purpose, where there were intrinsic purposes. This teleological world was comforting. Everything had its place, and purpose was an intrinsic feature of nature.

Over the centuries, this classical teleology (Neo-Platonists, Aristotle/Plato reconcilers) persisted. However, it came under pressure as scientific research increasingly pursued mechanical explanations rather than metaphysical ones. Thinkers such as Christian Wolff attempted to preserve teleology by declaring telos to be logical necessity, in an effort to make teleology systematic and rational. Meanwhile, the natural sciences were moving in a different direction (Darwin, etc.). In the 20th century, biologist Colin Pittendrigh proposed an entirely different idea called teleonomy. According to him, purpose is not within nature's structure, but emerges from the combination of adaptive processes. Organisms behave as if they have goals, but these "goals" are products of evolution, not of some cosmic intention. In other words, nature's behaviour appears to us as if it has purpose, but it does not. Teleonomy transformed fate into repetition, essence into feedback, and ultimate causes or purposes into selection. The bird does not build a nest to realise its Platonic essence. It builds a nest because countless generations of birds that did not build nests failed to survive, but its generation succeeded.

This shift from teleology to teleonomy reflects a deeper transformation in our understanding of humanity. If nature does not operate according to predetermined ends, then on what do we base humanity's meaning (and, of course, its importance)? Is everything now meaningless? Immanuel Kant attempted to reconstruct a moral teleology without metaphysics. He insisted that purpose comes not from nature, but from the structure of the human reason. We impose universal, principled, binding laws upon ourselves, and through this autonomy we create a moral world. According to Kant, the universe may not have an inherent meaning, but we humans do, because we have the ability to act out of a sense of duty rather than impulse. Purpose was not inherited; we created it, defined it...

However, Kant's confidence in this rational autonomy did not survive the existential upheavals of the 19th and 20th centuries. Søren Kierkegaard (the lonely man) pulled human purpose radically in a personal direction. The world offers no universal plan, he said. Meaning lies not in logic, but in commitment, in responsibility. Purpose is an action taken in full awareness of uncertainty. Where Aristotle saw purpose as essence, Kierkegaard saw it as an existential choice. The individual stands alone before the unknown and discovers who they are through resolute commitment.

When we reach Jean-Paul Sartre (the man with the pipe), the break with classical teleology finalizes. He has a famous saying: "Existence precedes essence." Nothing, neither nature, nor God, nor society assigns us a purpose. We are thrown into a world (by our mother) without inherent meaning and then, through our actions, we create meaning for ourselves. Sartre transforms teleology into radical freedom. Humans are condemned to invent their own telos. The hammer we make has no such problem. We who make the hammer also grant it its purpose. Albert Camus (the smoking man wearing a trenchcoat), however, takes a harsher but more humane approach. Fine, the universe was not designed for us. The universe is indifferent. It does not care about us. It is even absurd. But meaning can emerge through resistance, creativity, and solidarity. Purpose may be a work of art carved from the stone of existence, it does not wait for us to discover it.

From Plato's eternal Forms to Camus's courageous resistance and rebellion, one thing is clear: purpose has been transferred from heavens and from the universe to human action. What began as the metaphysical structure of the universe has transformed into a process of creation, interpretation, and adaptation. While teleology proposes an unchanging order, a construct, teleonomy explains evolving systems. Existentialism, meanwhile, explores how humans fill the void between the two.

In the dynamic, unpredictable, complex systems we inhabit, where everything is interconnected, the old hunger for a fixed telos may be understandable, but the dream of seeking harmony in this universe is misleading. We do not live in an Aristotelian universe where outcomes are predetermined, nor in a Platonic universe where purpose is pre-written above. Instead, we live in a teleonomous world shaped by feedback, adaptation and emergence. And in this world, purpose becomes existential. It is a purpose we choose, shape and bring to life (the responsibility is ours, do not blame others).

However, this does not diminish the importance of meaning. Quite the contrary, the absence of an immutable telos encourages our creativity. The loss of a predetermined purpose makes room for collective innovation. Like Pittendrigh's organisms, our actions are shaped by the patterns we create and reinforce. Like Kant's philosophers, we can choose principles to guide us. Like Kierkegaard's knight of faith, we can commit ourselves to what matters. Like Sartre's free man, we can define ourselves, and like Camus's rebellion, we can embrace life even in uncertainty.