In "Logic in the Wild," I advocate for the notion that logic serves as the guardian of coherence. This role entails analyzing reasoning structures, patterns of inference, and the interconnectedness of beliefs and theories. To those familiar with logical terminology, coherence relates to validity as cogency does to soundness. Importantly, coherence does not equate to truth. It's possible for scientific or theological theories to be coherent without necessarily uncovering truth. History offers ample examples, from ancient theories of optics and astronomy to modern debates on the existence of God.

Despite its significance, coherence remains an elusive concept, taking on different meanings in various contexts. A thought-provoking question arises: How far can we extend this concept? To explore this, consider the concept of harmony, traditionally associated with music and defined as a pleasing combination of sounds. Yet, its roots extend deep into European scientific thought, influencing astronomical, geometrical, and moral theories long before the development of intricate musical harmonies.

In Ancient Greece, harmony meant not only melodious sounds but also the arrangement of celestial bodies and the balance of the soul. Music provided a sensory gateway to harmony, inspiring deeper intellectual pursuits. This search for balance encompassed the entire universe, individual souls, and everyday life. The notion of the "harmony of the spheres" is a pivotal concept in this historical narrative, depicting the universe as playing a harmonious tune through the movement of celestial bodies. Johannes Kepler, profoundly influenced by this idea, used complex geometries to formulate laws of motion still relevant in classical mechanics. Newton's third law of motion, known as the harmonic law, directly stems from this line of thought.

In a surprising turn of events, while developing a new geometrical approach to astronomy, Kepler inadvertently laid the foundations for what we now know as modern harmony. This leads to a compelling question: Can harmony be seen as an extension or embodiment of the concept of coherence? Is the pursuit of a unified structure, linking the movements of stars and the human soul, essentially a quest in safeguarding coherence?