Of course it would be a huge exaggeration to say that the basic underpinnings of modern cosmology were laid down by just two people, but with these two people, it’s not quite as much an exaggeration as you might think.
The first of these you’ve probably heard of. Sir Isaac Newton lived from 1642 to either 1726 or 1727, depending on which calendar you use. Newton, among other things, formulated the laws motion and gravitation, and he was conspicuously high on all the lists of “most important people of the millennium” that started cropping up 20 years ago.
In contrast, you may not have heard of Gottfried Wilhelm Leibniz, a contemporary of Newton, living from 1646 to 1716. He was a brilliant mathematician, philosopher and polymath. Few people know that Leibniz propounded the thesis that this world is the best of all possible worlds. Voltaire is much better known for lampooning that thought than Leibniz ever was for saying it. Newton got much better PR than Leibniz did, at least in the English speaking world. It’s possible he’s still a celebrated superstar in the German speaking world, for all I know.
There is one important and interesting thing they share. They both invented calculus, at roughly the same time, apparently with neither having any knowledge of or influence from the other. This caused them to hate each other later in life and also brought them the eternal enmity of math-phobes everywhere.
But why do I say they laid down the base of modern cosmology? Isn’t that a pretty steep claim? Well, yes it is. The vast upheaval of life in Europe that we generally refer to as the Renaissance was the product of the work and observations of literally thousands of scientists, artists, writers, philosophers, clergymen, politicians, merchants, farmers, and all other sorts of peoples- many of them non-European, it should be noted. As a rule, we are only taught the biggest and most famous names in school. Still, in the area of cosmology- the basic study of what does the universe really look like, and how does it work? In this area in Europe at the end of the Middle Ages there was a big empty hole. Newton and Leibniz, though they both stood on the backs of giants, did more to fill that hole than anyone else.
Medieval Europe had a fabulous cosmology. It was simple in concept, though wonderfully detailed and complicated in practice. It was elegant and beautiful. The only real problem with medieval European cosmology is that it had absolutely no relationship with reality (and some people would say that’s not really a problem). Medieval philosophers drew all the best bits of Babylonian, Egyptian, Greek and Roman cosmologies, and placed them in a firmly Christian framework. You probably know the end result. Earth, completely corrupt thanks to Original Sin, lay at the center of the universe. Concentric crystal spheres orbited around it, each one progressively farther away from the corruption of Earth, each carrying one of the heavenly bodies: the moon, the sun, the planets, the stars, and finally, farthest away and most perfect, God in his resplendent heaven. A wonderful system that worked very well, until humans began learning how better to perceive the universe around them. Then the beautiful mechanism fell apart.
Nowadays it’s rather fashionable to dismiss the intelligentsia of early 17th Century Europe, especially the Catholic churchmen who tried to stop the ideas of people like Copernicus and Galileo. Were they afraid of losing their power? Were they just too comfortable in their beliefs? Were they just stupid? The answer is no, it’s much more basic than that. Before Galileo, people knew their place in the universe; they knew what to expect, even if it wasn’t always pleasant. Galileo effectively wiped away certainty itself. People always resist that sort of change. The universe was simple; the celestial objects were merely part of the ultimate pathway to heaven. Now, what where they? What did they mean? What purpose did they serve?
To be sure, there were already scientists hypothesizing that the planets were worlds in themselves comparable to Earth and the stars were just like the sun, merely farther away. But what of the larger canvas upon which hung? What were time and space? What meaning did they have? In short, an answer was needed to the question of what a much later writer would call Life, the Universe and Everything.
Into this void comes Sir Isaac. He devised mathematics to better perceive the world around us, he comes up with equations that accurately describe how light and matter interact with each other, and in doing so he comes up with a new description for time, space and the universe.
Very, very, very simply, Newton says that the universe is a giant box. Time and space are simply some of the dimensions of that box. Distance between objects helps to determine how they interact. All in all it’s a very simple, obvious system, with God taking his place as the Transcendent Clockmaker.
Leibniz’s universe is much more complex, being made up of monads. Monads are immutable, indivisible, irreducible objects, somewhat analogous to the original Greek notion of atoms. Again very simply, what monads do is perceive other monads. Some do it better than others. Some form composites and become capable of feeling and reason and memory, but all monads, even the most simple, have perception. Literally, the universe is defined by the relationships between all the different monads.
It follows that the monads that make up a rock tend to be more simple than the monads that make up a chair. The monads that make up a chair are more simple than those that make up a dog or cat. Obviously, people perceive the universe better dogs and cats, and much better than chairs, but not as well as, say, angels. Of course, God perceives all created monads perfectly.
What about space and time, distance and duration? Well, space and time aren’t monads, so they obviously don’t exist. While we humans do perceive the world better than rocks or chairs or dogs or cats, we still perceive it far from perfectly. Space and time are merely constructs of our minds used to cover up those imperfections. If I could see you perfectly, there would be no need for the illusion of distance between us.
It’s easy to see why Newton’s straightforward “what-you-see is what’s really out there” approach won out over Leibniz’s dense, intellectual, non-intuitive world of monads. Indeed, for the next two centuries Newton and his clockwork universe did become the answer to life, the universe and everything. Ironically, this was not Newton’s intention at all. When he was criticized by people who pointed out that he never really explained gravity, he calmly pointed out that he never tried to explain anything with his laws of motion but only describe what he observed. It is very commonplace nowadays to say that Newton’s work has been wholly superseded by Einstein and relativity, but that’s not quite accurate either. It’s true that the clockwork mechanics don’t work at extreme velocity or gravity, but the box that Newton put the universe into is still there. It’s a box that is growing and may be very strangely shaped and filled with mostly empty space instead of clockwork, but time and space are still some of its parameters. It may not be Einstein who is the final nadir of Newton, but instead– Leibniz?
Strange as it may seem, Leibniz may be making a comeback. Actually, he has already made a comeback with his writings that have bearing today on subjects as diverse as psychology and computer science. But I’m talking here about his obscure and esoteric monads. For instance, we now know from physics that seemingly solid objects are mostly empty space, giving lie to Newton’s notion that about the relative accuracy of our perceptions. Also consider that we know from psychology and neurology that our image of the universe is just that– an image. Specifically, when we talk of seeing something, what we’re really doing is collecting light rays and other sensory data and sending it to the brain, which then constructs an image that we “see.” How well we perceive literally affects the universe around us. Indeed in physics it’s axiomatic that the very act of observation has an effect on the observed. Sounds rather like monads interacting with each other to me.
But I am most convinced by the influence Leibniz has had on our popular culture. Take for instance the movie “The Matrix” and its sequels. The central premise of these movies is that we are all attached to a giant tower that feeds electrochemical signals into our cerebral cortex, and from this we all create a shared illusion that we take to be the world around us. The comparison to Leibniz’s view about a universe made up of monads perceiving each other is eerie.
So perhaps Leibniz is making a comeback. Or maybe both Newton and Leibniz are both on their way out; I’m not nearly conversant enough with contemporary cosmology to say. Still, of all the backs of all the giants that current day cosmologists are standing on to see even farther into the future, the two biggest are still Newton and Leibniz.