Meaning: The quote by David Deutsch highlights the significance of theories that offer deep and profound explanations, rather than being limited to a specific scale or level of complexity. David Deutsch is a prominent physicist and author known for his work in quantum computation and the theory of parallel universes. In this quote, he emphasizes the importance of scientific theories that provide comprehensive and fundamental explanations, regardless of the specific context or scale to which they apply.

One interpretation of this quote is that it underscores the value of scientific theories that transcend narrow boundaries and offer explanatory power that extends across different scales and levels of complexity. Rather than being confined to a specific domain, truly privileged theories have the capacity to elucidate fundamental principles that apply universally. This perspective aligns with the idea that scientific understanding should strive to uncover underlying principles that can account for diverse phenomena, rather than being limited to specific contexts.

In the realm of physics, for example, privileged theories are those that can explain phenomena at both the macroscopic and microscopic scales, bridging the gap between classical and quantum mechanics. Such theories would not be constrained by the particular scale of size or complexity at which they operate. Instead, they would offer profound insights that hold true across different scales, providing a unified framework for understanding the behavior of physical systems.

Moreover, the notion of "deepest explanations" in scientific theories implies a quest for understanding that goes beyond mere description or prediction. These theories aim to uncover the underlying principles and mechanisms that govern natural phenomena, delving into the fundamental nature of reality. By seeking deep explanations, scientists aspire to reveal the fundamental truths that underpin the workings of the universe, transcending specific scales or levels of complexity.

Deutsch's emphasis on "the ones that contain the deepest explanations" also suggests a focus on explanatory depth rather than superficial breadth. In other words, a privileged theory is not necessarily one that covers a wide range of phenomena, but rather one that penetrates to the core of understanding within a specific domain, offering profound insights that illuminate the underlying principles at work. This perspective encourages a pursuit of depth in scientific inquiry, prioritizing the elucidation of fundamental principles over the mere accumulation of empirical observations.

Furthermore, the quote suggests that privileged theories possess a certain universality in their explanatory power. Regardless of the specific scale or level of complexity at which they operate, these theories offer insights that transcend narrow boundaries and extend to diverse domains. This universality speaks to the broad applicability and relevance of privileged theories, as they are capable of providing profound explanations that resonate across different contexts and disciplines.

In summary, David Deutsch's quote underscores the significance of scientific theories that offer deep and fundamental explanations, irrespective of the scale or level of complexity to which they apply. It advocates for a focus on explanatory depth, universality, and transcendence of narrow boundaries, reflecting a commitment to uncovering profound insights that illuminate the underlying principles governing natural phenomena. This perspective encourages a holistic and foundational approach to scientific inquiry, emphasizing the pursuit of comprehensive explanations that transcend specific contexts and scales.