Ever since the beginning of the modern era, science-based inquiry has extended our understanding of the world in ways unthinkable to our remote ancestors. Some changes have occurred slowly, while others have been rapid and transforming, especially over the past 200 years. While many implications of our growing knowledge are universally recognized, especially its effects on technological advances, a philosophical, or meta-analysis of the nature of acquired knowledge is more often left to professional journals, rather than widely-read periodicals written for non-specialists. But reflecting about knowledge, thinking about what knowing or understanding can really mean, are not trifling issues. They deal with enigmatic questions about the very nature of present-day science and knowledge in general. They deserve our close attention. The overall discussion will also serve as a retort to radical critiques of the very idea of evidence-based, honest inquiry in the sciences, disquieting viewpoints rejecting both the ideal and the possibility of universally justified facts and theories. This surprising and odd perspective views contemporary science as only one of many social factions projecting their societal power, arguing that science-based claims are epistemically no more legitimate or substantial than any other sub-group’s points of view.

We begin this complicated story by examining a sequence of epistemic principles that guide our species’ ability to study and better understand the cosmos:

Abduction: Inference to the Best Explanation. Much less formal than either deductive or inductive thinking, abduction searches for explanation (or hypotheses) that are consistent with all relevant information at hand, as well as consistent to what we already consider true about the world—beliefs carrying an overwhelming degree of confidence. Integrating the interrelationships of all information germane to a question is complex, requiring a high level of problem-solving skills. But notice this is a similar situation any of us might face as we live our complicated lives and work in challenging circumstances. Not surprisingly, abductive thinking has been described as a messy process, unlike the clarity of formal logic, but that quality makes possible its adaptability and fecundity. Emphatically, the abductive frame of mind is not exclusive to science, but lies at the core of most successful problem-solving tasks. Abduction deals with likelihoods, not certainties, and must remain open to new, relevant information if it is to provide the most effective solutions or hypotheses. This is what makes abduction an iterative process, and justifies a well-formed abductive process being judged an “inference to the best explanation”. Further, abduction’s open-ended, empirically based process is most effective when complex issues in science, engineering or other fields, are approached collaboratively, providing a check on individual biases, and further stimulating creative thinking.

Universal Concurrence. Contemporary science, throughout every discipline, is global in practice, fully cross-cultural in its research, innovation, vetting and application. What was once primarily the project of 18th century males of the European Enlightenment has evolved into a world-wide, interconnected phenomenon no longer gender, culturally or geographically specific. And the influence of science-based reasoning affects every tier of income within specific societies and nation states—digital technology has permeated every corner of the planet, leaving no one untouched. Only a universal science could have such impact. This brute fact becomes a severe challenge to any radical critique of the efficacy, relevance and universality of corroborated, well vetted science.

The Iterative, Provisional Character of Theories. Even conceptual frameworks as firmly accepted and supported as genetics and natural selection—justifiably recognized as established knowledge—are subject to clarification or modification whenever new inquiry brings important, new information. This is what is meant when philosophers of science argue our knowledge of the world is not absolute, although some explanations (theories) may represent a very close approximation to reality. Neo-Darwinism, the Modern Synthesis in biology, is placed in this category, as well as recent advances in neuroscience.

But acknowledging the most powerful theories and concepts of scientific inquiry remain open to revision, does not imply we should not accept, as established, important facts and truths about the world—we can say many assertions are actually true. Clear examples are the role of DNA in genetic patterns and replication, the neural structure of the human brain, the similarities in the architecture of the nervous systems throughout all mammals, and uncounted others. The mass of known facts gives the very idea of truth its intellectual power. But keep in mind this is “truth” in lower case letters.

Like all human activities, scientific work is a social institution imbedded in the larger society, influenced by any number of social forces, both positive and negatives. But in the long run, biases and misperceptions are corrected by the collaborative and evaluative roles of world-wide peers. This self-corrective function is not infallible, but is central for the advancement of well-grounded science. Scientific inquiry could flounder without it. Even Thomas Kuhn’s “scientific revolutions” find their eventual success through peer critique, evaluation and eventual acceptance by the greater scientific community.

Consilience--the Unity of Science. One of the more interesting terms characterizing contemporary science is consilience, a word with an ancient origin, and popularized by E.O. Wilson in his book of the same name. Wilson used consilience to describe the explanatory impact of synthesizing evidence and theories from different fields of inquiry. A model example is Neo-Darwinism, a theory supported by evidence from genetics, molecular biology, paleontology, comparative anatomy, embryology and others. A background of information drawn from varied disciplines produces a forceful consensus, increasing the likelihood of a uniquely useful explanatory theory. A similar story connects Quantum Field Theory—and its varied implications—to electrical engineering’s legion of electronic creations we use today. Without Quantum Field Theory much of our technical civilization could not have been devised. More generally, physics, chemistry and biology form a consistent story from the very small and simple to the large and complex—from the simplest life forms to complicated, conscious humans—and from subatomic particles to galaxies and the vastness of the observable universe.

Realism, but with Serious Caveats. Model (or theory) dependent realism, and structural realism, are two concepts used in the philosophy of science to capture what knowledge in science really means. Both make the fundamental existential assumption of an objective reality, the cosmos—the whole—and includes us among everything that is. And as part of that whole, humanity is imbedded in its structure and cannot observe the whole in its totality. We are intrinsic to it, unable to stand outside the whole—the cosmos—and observe all aspects of objective reality (the very phrase, “standing outside the whole” is non-sensical). This is another way of saying complete knowledge of reality is not possible. In its stead, both model dependent and structural realism stipulate how reality is interpreted through theories (or models). Models will not be exact mirrors of the world, but are understood as approximations mediating reality. Yet knowledge evolves, as increasingly more useful models are sequentially developed, accounting for and relating more data, carrying greater explanatory, descriptive and predictive power. A definitive example is Einstein’s development of General Relativity, a model superseding Isaac Newton’s late 17th century interpretation of gravity. While Newtonian physics remains useful in engineering and some aspects of physics because of its simplicity, its applicability is not as broad as General Relativity, making GR the more powerful conceptual tool, describing a wider range of phenomena.

In this essay, realism is softened by the above caveats, treating reality as incrementally approached by scientific inquiry. The prior assumption of an objective reality is simply presumed—a point of view taken through abduction and one that is eminently sane. But an issue deserving more attention is what it really means for reality—the nature of the cosmos—to be imperfectly interpreted, and just why any interpretation offered should be viewed as incomplete, in an important sense.

As presented above, both structural and model dependent realism assume we cannot know things-in-themselves (or reality-in-itself, or the totality of reality). The late 18th century philosopher Immanuel Kant emphasized this epistemic barrier in his Critique of Pure Reason, concluding the human ability to experience the world is constrained and given by the structure of our mind—a condition of our existence shrouding ultimate reality. Things-in-themselves exist and contribute to our experience, but their intrinsic nature is outside our intuitive grasp. Human knowledge, though impressive, can never be absolute. Structural and model dependent realism have reformulated this concept, where what really matters in scientific inquiry is grasping and quantifying the observed relations between things, since we can never know, in an intuitive sense, their intrinsic nature. This predicament is confronted whenever we try to grasp the intrinsic nature of what we consider ordinary phenomena, such as mass and gravity.

Both mass and gravity are ubiquitous in scientific as well as every-day descriptions of the world, but what we really know is how the relative mass of objects relate to one another—how massive bodies affect each other through their gravitational fields. Can we understand something about mass beyond these observed and predicted patterns? I remain skeptical of the possibility of intuitively grasping the nature of mass—its intrinsic nature. Yes, current models provide exceedingly accurate and consistent predictions, and current concepts—gravitons and space-time—enrich our understanding by offering fuller descriptions of phenomena, but augmented descriptions do not transform our understanding into something different in kind from highly sophisticated operational descriptions. When more comprehensive models of gravity result from future research in fundamental physics, they will remain operational descriptions at their core, even if we describe them as offering genuine knowledge . Asking for more than this—a kind of first-person acquaintance or intuitive prehension of a phenomenon like gravity—does not reflect the epistemic limits—and structure—of the growth of knowledge. Any unease with this inherent constraint—a lack of absolute understanding—will subside once we realize the only access to certain, intrinsic knowledge is our first-person awareness of individual, subjective experience—our phenomenal consciousness.