This is a fascinating read, one of the few books I'm aware of that really straddles the fuzzy border between science and the humanities. It is difficult to characterize this book along many binaries, maybe even between fiction and nonfiction, depending on how literal you wish to take things. However, it is most certainly intended as nonfiction, and I'll proceed with that interpretation.

The Cosmologist's Second (1991) is not a technical book (there are no equations in sight), nor is it purely a popularization of science. Instead, it is an accessible philosophical work about cosmology at large. And by "large," I mean gargantuan. Here, “cosmology” means “any attempt to explain why the universe is how it is,” encompassing not just modern scientific orthodoxy, but a perspective that is holistic enough to include not only how pre-scientific civilizations studied and asked questions about the universe, but any possible future theory. A task for the generations, but the goal here is simply to introduce some of these considerations and to relate some of the milestones in its development. No specialized knowledge is assumed; you need know little more than that the Earth lies in a solar system in the Milky Way galaxy.

Rudnicki is an astronomer by profession, but is also an ordained priest, a son of two radical leftist revolutionaries, and a follower of Goethe’s humanistic approach to science and in particular its realization through anthroposophy, an esoteric spiritual movement with roots in German idealism (e.g. Kant, Hegel), Theosophy, and Christian Gnosticism. Such a combination was perhaps not unusual in the time of Copernicus or Newton, but is a rarity in the era of professional science. There are many interesting rabbit holes to go down on background alone, but for purposes of review, I'll focus on the main questions about the book's content. Namely, what does non-scientific thinking offer for cosmology? Why step outside the box when physics can explain most of what we observe in the universe? And if a theory can encompass everything, how can it be saying anything interesting at all?

It's important to clarify that Rudnicki is no crank, nor are these the senile ramblings of some emeritus that we politely ignore out of some sense of collective magnanimity. While there are shadows of New Age ideas due to the subject matter, this is not a book on sacred geometry or how the great yogis secretly understood the Einstein Field Equations. Rudnicki firmly states that the methods of the ancients cannot be fruitfully applied to modern science, that even the best such efforts "have come a few thousand years too late." However, he states that the scientific approach has its limits as well, and more importantly, it is not how the people of the past thought, nor is it likely to be how future generations will think about the universe. So what would a theory look like, if instead of rejecting anything but the present down-to-earth methodology of modern scientific practice, it somehow were able to incorporate all of these developments under the same umbrella?

Rudnicki's overarching thesis, steeped in his non-astronomical roots, is that the relationship between scientists and science has changed dramatically over the course of civilization. Specifically, there are two long-term simultaneous forces at work: on one hand there is a steady evolutionary progress, and on the other there is growth, bloom, and decay. A core belief of anthroposophy is that all social and cultural relationships––not only between scientists and science––are repeated innumerable times, but never twice in the exact same form; to this end, its founder Rudolf Steiner (now best known through Waldorf schools) divided human history into "great epochs" corresponding to the periods of this "wavelike" development. This is where things start to go wobbly. For one, the belief is that the last great epoch before the present was that of Atlantis, and before that, Lemuria. Even in the present great epoch, we live in the fifth post-Atlantean culture, after smaller epochs that are referred to via the great spiritual culture at the time: India (~7000–5000 BC), Persia (~5000-3000 BC), Egypt–Babylonia–Chaldea (~3000–750 BC), Greece–Rome/China (~750 BC–1400 AD), before arriving in the modern "West" starting around the time of the Renaissance. If modern history is the view of civilization from 10,000 feet, this view is something you'd need the James Webb Space Telescope to perceive our present day.

OK, you might say, we're already in crazy cloud cuckoo land. How can a credible scientist seriously mention something like "Lemuria" in spite of a concrete scientific consensus like continental drift ruling out the existence of some lost continent? The basic response is that such a view is too materialistic, too narrow-minded, too literal. It's not about evidence that stands up to scientific scrutiny; Rudnicki freely admits that there is no convincing physical evidence even of the later great epoch of Atlantis. Instead, the point being made is that cultural changes can't be understood from physical effects alone, but must also incorporate the spiritual and psychological effects. Moreover, signs seem to indicate that the latter acts more directly, with the former being essentially an after-effect. Such thinking is perhaps most familiar today through Jung's concept of the "collective unconscious." Like Jung, the anthroposophic belief is that this vast hidden world, while opaque, is amenable to exploration, and in a systematic way at that.

For example, in this view, the fact that philosophy arose simultaneously in Greece and China, despite their lack of cultural relationship at the time, is no accident, but rather the manifestation of the greater non-physical processes. Roughly speaking, it is the changes in consciousness that call forth changes in the external social and technological life, which in turn trigger further changes in consciousness, which drives further changes, and so on. Awareness of the physical world, the capacity to measure and shape, the development of logic and deductive thought are all important examples of developments in consciousness, marking some peaks of the recent smaller epochs. It is with this background that Rudnicki examines concrete problems of 20th century cosmology.

A reason to consider unorthodox viewpoints is that they often highlights implicit assumptions underlying our current thinking. A famous one in physics is that of the Euclidean model that we learn in high school: one where the laws work the same from every point in space and time, in particular. While this is a great model, simplifying centuries of insights and usable on most "everyday" problems, we now realize that the universe is in fact non-Euclidean, a fundamental observation underlying Einstein’s theories of relativity. Actually, it does matter which point you're measuring from, because there is a near-imperceptible curving that occurs, a difference that becomes pronounced when talking about things that are big or fast. (Without such considerations, GPS, for example, would be far less accurate and desync constantly.) Our collective understanding was blocked by an implicit assumption, and it took a once-in-a-century genius to overcome it. Or, adopting the big picture perspective above, it took us the time and effort for consciousness to develop to the point that such an idea could be thought and expressed and spread. Great man theory, eat your heart out.

To make his point, Rudnicki gets to the nitty gritty. He emphatically points out that even our most precise scientific models rely on a rickety foundation of assumption after assumption, affecting the questions we ask, our interpretations of the facts, and what even counts as an "answer." This is pursued through a few examples, from the Copernican heliocentric model of the universe to the Hubble constant to the Big Bang theory and steady-state model. It is insightful, concise, and among the best expositions of the web of dependencies that our modern models rest on. Even if you ignore why Rudnicki is doing all this, these explanations are great; indeed, it seems like portions of the work were published before in Polish popular science journals.

An important example––the main one of the book––is what does “a second” mean to a cosmologist? We think of this as an absolute measure that we use all the time without thinking. Nevertheless, if we pause for a moment, we see that the notion of "second" is problematic, a fact that is increasingly obvious on cosmic timescales. The universe is not a perfectly tuned clock. The lengths of days (either sunrise to sunrise or even the more robust notion of full rotations of the Earth) vary during the course of the year, the lengths of years (full revolutions of the Earth around the sun) vary across centuries and millennia, and what about times before the solar system existed or long after it is dissolved? The origin of the standard notion of second is shockingly arbitrary: it is 1/31,566,925.9747 of the tropical year (a full revolution of the Earth) on December 31, 1899 at 12 hours ephemeris time (the standard astronomic timescale)! (This was adopted because it was used by Newcomb's Tables of the Sun (1895), a popular reference for such calculations for most of the 20th century.) The modern atomic time, based on the decay of cesium atoms, was made to match this "second," and with this, we have a notion of "second" that can at least extend to when such atoms exist. However, in the first few "minutes" after the Big Bang, there are barely even hydrogen atoms, much less anything as complex as cesium, so what should "second" even mean here? We've hit the boundary of our precise understanding, and must make even more assumptions if we wish to proceed. In short, there is no "true" "cosmologist's second"; it is only an abstraction, a name we give to different units so that it easy to think about them, a notion that co-evolves with our models of the universe.

This is not even the end of the story; we haven’t even gotten into the complications of relativity and loss of notions like “before/after” or “simultaneity” with respect to time. Rudnicki does not get into this, but the point is made. All physical constants and laws assume at least a locally homogeneous notion of time, but this is but a simplifying assumption of the model, not a reflection of the “true” world, if such a thing even makes sense. In other words, never forget that the map is not the territory, even when the map gets big enough and immersive enough and accurate enough that it becomes hard to distinguish between the two.

So what are we supposed to do now? Is this all a hopeless task? Is it a foolish game to try and understand the cosmos? No, of course not. Theories rise and theories fall, and while there is no guarantee that science will continue to advance, we at least seem to know much more than we did at least as far back as recorded history. In the final chapters, Rudnicki suggests that humanity will evolve higher forms of consciousness, as incomprehensible to us as science would have been to the ancient rishis the Vedas are attributed to. Not that we should turn away from modern scientific research, which has been phenomenally successful in understanding the material world, but we must also realize that the consciousness of the existence of spiritual beings should be developed, along with methods of research appropriate to the task. By remembering the limited scope of validity of the models, we see the vast regions where measurements do not apply and our current concepts of space and time reach their limit, and may only be overcome by extending and supplementing our consciousness, perhaps in ways we cannot realize at present. We may laugh now at medieval philosophers arguing about how many angels can dance on the head of a pin, but it is through such debates that things like logical thought developed into prominence.

The Cosmologist's Second is a compelling message to really, truly examine your assumptions, no matter how "obvious" they may seem, and a grand perspective and glimpse at the vast potentialities that are just waiting to be discovered. Not many books can convey that sense of wonder, of sheer possibility, in a modern world where it seems like everything is known, boxed in and tabulated, where all we have to look forward to are rehashes of the past. But Rudnicki points to the anomalies, the inconsistencies, the paradoxes that seem to indicate that all may not be as it seems, and even if you don't buy what he thinks is a good way to resolve them, that doesn't deny that the things he pointed at are weird indeed and worthy of investigation. An inspiring call to action, not by mustering the masses and giving orders, but by teaching us to yearn for the endless reaches of the universe. Wir müssen wissen. Wir werden wissen. We must know, we will know.