Are some things off limits to our possibility of knowing? Should science speculate on them? How about the realm that is beyond what we can collect evidence of? What would Kant say?
Science surprises us with the size of the universe, although some philosophers may have been less surprised than others. Nebulae were known to astronomers at least since the year 964, when Persian astronomer Abd al-Rahman al-Sufi wrote about the little cloud in the constellation of Andromeda. However, as I mentioned in the former post, scientists did not suspect this and other nebulae to be objects outside of our galaxy until the eighteen hundreds. The matter became controversial and was the subject of what came to be known as the Great Debate of 1920, in which astronomers Harlow Shapley and Heber Curtis presented opposing views on the subject. Shapley took the view that nebulae such as the one observed in Andromeda are objects within our galaxy, while Curtis maintained that objects such as these are galaxies in their own right, far beyond the Milky Way. As we saw, the matter was definitely settled by Edwin Hubble and his analysis of variable stars presented at the beginning of 1925.
But 170 years earlier, the idea that these nebulae were extragalactic had already been put forward by none other than the philosopher Immanuel Kant. What in the world was Kant doing observing and theorizing on Nebulae, one might wonder, and how is it that he correctly reasoned that these objects, in particular M31 was a galaxy similar to our own? Kant was, in fact, quite interested in astronomy, and correctly noted that the stars we see in our galaxy lie on a plane. This is the same plane our solar system is on, and looking toward the area of most stars we see a white cloud which is actually the profusion of central stars which give the Milky Way its name. If we were to look at it from very, very far away, it would appear like a cloudy ellipse, intrinsically extremely bright, but in appearance faint because of the distance. Kant realized that a faraway Milky Way would look just like what we see when we take a look at some of the nebulae he had studied, including, of course, M31, the Andromeda Galaxy. The Milky Way was considered the universe then, so what Kant understood that he was observing were other universes. It seems he was not at all afraid to embrace this idea of universes beyond our own. In his own words, from his treatise Natural History and Theory of the Heavens, he explains “these higher universes are not without relation to one another, and by this mutual relationship they constitute again a still more immense system”
Remarkable as his insights on the universe are, small-framed Kant’s towering influence on our concept of the world is not due only to his observations in astronomy. Kant made a significant contribution to our understanding of the size and structure of the universe, but, of course, he is mostly known and revered for his thoughts on how we perceive and understand the world and the objects we interact with. In his famous Critique of Pure Reason, he distinguishes between the noumenon, or thing in itself and the phenomenon, or what we perceive of that thing. The noumenon is, according to Kant, essentially unknowable. All that we experience of the world is the phenomena which we perceive. The relationship between the noumenon and phenomenon is tricky. How can you not know anything about the noumenon while engaging with the phenomenon? In the view of Donald Hoffman, author of “The Case Against Reality, Why Evolution hid the Truth from our Eyes” what we perceive is radically different from what is because our perception has been tuned to detect fitness benefits and not reality, or we would never have survived as a species. Not to get too far off topic, in simple terms, we can say that Kant divides the world into Phenomena and Noumena. What we can know about objects is what we can experience, nothing else. There is no contradiction in this philosophical view with the proposal that nebulae are galaxies and our universe is far larger and contains far more stars than we thought. With very little evidence and tools, but with great insight, Kant boldly theorized that the current view of the universe was way too parochial. This from a man who rarely left his town, and never travelled far. When the Astronomical Society heard Hubble’s results in 1925 confirming the concept of a universe with other galaxies besides our own, we can only imagine Kant, the pleased philosopher looking down on these scientists, five generations removed from him, “See kids,never underestimate our capacity to reason.”
But what about the stars that wink out of our observable universe every second? Or the possibility of universes beyond the limit of information that can ever reach us? Would Kant be equally enthusiastic about these new additions to our concept of reality?
Humans relentlessly pose questions. It could be said that this is a defining quality of our nature. Our minds are constantly occupied with posing questions and obtaining answers. We are, you might say, addicted to questions and answers. Getting answers is akin to completing things. When we put together a puzzle, questions begin to populate our consciousness in rapid succession. Where does this piece go? Does this look like a piece of sky or water? Where is the corner piece? And each answer gives us a brief sense of gratification. We feel most gratified when we finish the puzzle, having answered all questions. But if a piece is missing it is disproportionately annoying. We want all the answers, not 99% of them. Our desire for answers and completing things can often lead us to incorrect conclusions. Our vision sometimes completes things which are not really there. Optical illusions in which we mistakenly “see” a triangle or a complete cube when portions are missing, abound. Many of our questions have simple, immediate answers. Some of them are more difficult. And some do not appear to have answers at all, or, at least, no answers grounded in evidence. But we seem to come up with answers anyway, no matter how speculative or divorced from experience. It seems that often an absolutely arbitrary answer based on no evidence whatsoever is better than none. When we hear the answer, nobody knows, it is almost always immediately followed by, but … and some speculative answer.
In the past, every culture, it appears, had answers to the question of the origin of the world and the creation of humans. Some had to do with a thought, word or offspring of a divine being, others spoke of a fantastic animal, a great sea serpent, bird or spider, a God that eats its children, a being that is dismembered to form the earth, experiments to form a human with mud, wood and corn, a universe which is destroyed and re-created in cycles, a universe which was never created but has always existed. We know of many, and there are surely a great deal that have been lost. Today, thanks to technology that can detect vanishingly faint clues that the universe provides, we have a great deal of answers available to us that are based on solid evidence. We have assembled a good portion of the puzzle; much, much more than ever before. We have a good understanding of how the earth was formed and evolved. We know how the stars, including our own sun were formed. And we have a widely accepted theory on the formation of the universe, dating back to a few fractions of a second after the Big Bang. Pieces of the puzzle have fallen into place one after another providing us with a detailed image of a great chunk of the process of how the universe formed. But some pieces are missing. Why did the Big Bang occur in the first place? Is our universe the only one? How large is the unobservable part of it? The answers to all three are “Nobody knows, BUT…”
Anyone can speculate, but scientists have the tools of mathematics that make their speculation at least more consistent. One thing that is pretty clear, as we explored previously, is that part of our universe is unobservable, and stars and other objects at the edge of our observable universe are constantly entering the unobservable part, so that we can never see or know of them again. The universe is made up of a part we can observe and a part, which, by definition, we cannot. This is not exactly what Kant was referring to with his realms of Phenomena and Noumena, but there is an interesting parallel. Kant explains that we form our concept of the world based on two types of knowledge: a priori knowledge, that which we acquire independent of experience, and a posteriori knowledge which we gather from experience with the world. Our a priori knowledge, which, according to Kant, includes the concepts of space and time, is like a built in, hardwired feature of our minds. All our a posteriori knowledge comes from observed phenomena. However, there is a fundamental reality which is the essence of what we observe, the thing in itself, or Noumenon. Kant’s Critique of Pure Reason is long and challenging to understand for even the experts, and certainly very difficult to understand, and easy to misinterpret for a non-expert like myself. But I would venture that what he is actually saying about the noumenon is that its existence can only be perceived by a consciousness beyond, or perhaps different than our own. The noumenal world exists, but it is the phenomenal world that we perceive.
Phenomena from the observable universe has allowed us to create a model of it, but that model now points unequivocally to the existence of a place, similar to our observable universe, from which no phenomena can, by its very nature, be detected from where we are. This is a truly remarkable state of our knowledge. It is also something that has never happened before in the realm of science: We know of a place from which we can gather no information. Where, in philosophical terms does the unobservable universe fall? Has it been subsumed by the noumenal? And, if we ever discover or create a wormhole through which we can travel to that area of the universe, would it once again return to the realm of the phenomenal? Physicists don’t seem to worry too much about these questions, but, requiring puzzle pieces no one can see to complete your puzzle may seem questionable. At least the stars that leave our observable universe were once observable, but what about the concept of multiverses, which we never could or can observe? Physicists will argue that, if we follow the math, and the math of our model leads us to non-observable things, we should accept this as a reasonable possibility, and give it greater weight the better our model explains the things we can observe. This faith in math was what led to the, initially puzzling solution to Paul Dirac’s equation which included an electron with negative energy. This anti-particle was viewed with skepticism at first (even by Dirac) but a few years later was experimentally confirmed to exist. Positrons, as they came to be known are now not only known to exist, but are used routinely in Positron Emission Tomography: PET scans. So if the math points us to many universes, we should not be afraid to consider them a possibility. Of course, there is always the “Tree falling in the Forest with No One Around to Hear it” issue which we considered in the former post. If there are other universes which are undetectable, do they really exist to us? Is there an implication that there must be some consciousness that can sense them to justify their existence? Or simply, does the power to imagine something make it possible?
In Walt Kelly’s famous comic series, I recall a scene featuring the multi-talented possum Pogo with his alligator friend Albert on the banks of the Okeefenokee swamp. The two friends are lying on the ground with nothing much to do, so Pogo suggests they play the game of imagining the biggest catfish. Albert agrees, and after some moments of thought, each friend puts up his hands indicating how big his imagined catfish is. Pogo’s was a bit larger, so he wins the game. I may be getting the characters involved in that scene mixed up, and am missing their actual dialogue; sadly, I was not able to find the original comic strip. In any case, playing this game apparently requires not only uncommon honesty but also an imagination that is limited to things seen before, otherwise, the imagined catfish would get too big to compare results and declare a winner. Aside from the humor, the point is that, unless we are a Pogo character, we can, of course imagine catfish much larger than we have ever seen. Possible, but not necessarily real, catfish (or universes).
Catfish notwithstanding, can we accept the existence of imagined universes that are vast and unobservable because they may be implied by our theories? Kant never considered the multiverse in the sense it is thought of today. He did, however, write about the noumenal world which he believed existed but was off limits to us. With his ponderings on the nature of reality, Kant’s insights seem surprisingly relevant to our question. To rephrase, what we are really asking is: Can our knowledge of the universe based on phenomena as well as our a priori system of knowledge lead us to the valid concept of a universe from which no phenomena can be detected? Kant’s positing of the noumenal world seems to me, at least, to answer that question with a yes, we can. Kant reasoned correctly about the Andromeda Galaxy. He may be the right fellow to turn to when considering the multiverse as well.
LINKS
Photo from blackwatercats.com. No info on who the amazing fisherwomen are or which catfish is bigger...
Comments