How many things are there in the entire universe? (This is a trick question.)

A physicist argues that many mysteries start to clear up once you accept that there is just one thing — the universe itself.

Sandro Botticelli's "The Birth of Venus," 1484-85. Heinrich Päs writes that this depiction of the goddess of love was an expression of monistic philosophy. Love is an ancient symbol of unity, and here Venus is being swept across the sea to take on a corporeal — yet cloaked — existence as nature.Public Domain

You and I and every blade of grass, every rock and every mote of dust, and every star in every galaxy — what are we all made of? Atoms. What are atoms made of? Protons, neutrons, and electrons. But there are still more subatomic particles, like quarks. So then what is the essence of those particles?

Physicists have been trying to analyze reality in ever more granular detail under the assumption that this will make it possible to understand more deeply why the universe is as it is. How exactly does gravity work? What is going on in black holes?

The answers to these and other mysteries remain elusive partly because quantum physics — the study of matter and energy at their most fundamental level — yields so many weird results. Because of the phenomenon of entanglement, seemingly individual things affect each other even over long distances. And any attempt to study fundamental particles is thrown off by the mere fact of the observation.

Heinrich Päs, a professor of theoretical physics at TU Dortmund University in Germany, thinks his field is generally looking at things backward. Rather than trying to understand the universe by analyzing its smallest tidbits, Päs argues, the best way forward is to see all those grains as portions of one unified whole. In his new book, “The One: How an Ancient Idea Holds the Future of Physics,” Päs shows why quantum physics is indicating that all things are connected — which also happens to be a conclusion that many religions and philosophies reached long ago.

My interview with Päs has been condensed and edited.

The eminent physicist Richard Feynman supposedly said that if you think you understand quantum mechanics, you don’t understand quantum mechanics. But I really do think I understand your book!

OK, that’s good.

You write that the idea that everything is one — monism — can be found in ancient religions, Greek philosophy, and all the way up through the Renaissance. If this is actually not a new idea, why are we now in need of being reminded of it?

It took me some time to realize how straightforwardly this idea — that all is one on the fundamental level — really follows from quantum mechanics. Then the next question is: Why is this not prominent? Why is it not more often discussed? Why does it still sound so esoteric, like New Age BS? So I started to look at the history of the concept. And I was quite amazed that I found this truly amazing story — like a Dan Brown novel.

It’s true that these ideas are very ancient. You can find them in ancient Egypt and in many ancient philosophies and religions. Plato had some kind of secret doctrine about these ideas. And then, as I understand it, the problem arose when Christianity appropriated this idea to some extent and mixed it up with other ideas.

The idea that all is one on the fundamental level is called monism. The opposite is dualism — that there are two forces, like good and evil fighting against each other. You have a strong influence of dualism in Christianity. Think of angels and demons and heaven and hell and so on. So this monistic idea, the concept of an all-encompassing one, was pushed out of the natural world to some transcendental realm reserved for God alone. Organized Christianity, the Church, was very eager to make sure that the natural world wasn’t seen as mixed up with this transcendental world. And I believe this is an important reason why we don’t take it seriously as a concept for science, as a concept to describe nature.

Heinrich Päs, a professor of theoretical physics at TU Dortmund University in Germany, is the author of "The One: How an Ancient Idea Holds the Future of Physics."EMILIA VON DOMBROWSKI and BOGUMIL LONGOWSKI

As for feeling like part of a Dan Brown novel: You say the thread of monism runs through paintings such as Botticelli’s “Birth of Venus.” How do you know this is not just a modern, selective interpretation and that even at the time it was noted and possibly controversial?

We know philosophers were quite explicit about these ideas. In the Renaissance, Marsilio Ficino, a philosopher of Florence, was trying to revive Platonic ideas about oneness, and he wrote a lot about it. He was quite influential, and Botticelli, a Florentine painter, was affected by these ideas.

Why do you think it would be useful for people to embrace or be more open to monism today?

I mainly consider it as a concept we should take seriously for physics. But of course I’m also interested, if this turns out to be a fruitful concept for physics and a good description of the universe, in what that would mean for us.

I think what is good about monism in its pure form is that it could help us to overcome these dualist notions that we think in black-white categories and good and evil, and to see that people who have other interests or other political opinions maybe have similar problems or similar motivations. Maybe it could help us to be more cooperative and not so polarized. And it also could come with a sense of responsibility about nature, for example, since it stresses that we are part of nature.

I’m not claiming that this is the answer for developing an ethical lifestyle, but my main point is that we should take this idea of monism seriously as a concept of science and see what we can do with it. I think many physicists have the idea that physics is only experiments and mathematics and you don’t really need an intuition of this picture behind it. I don’t agree with that.

Particle physics is "more precise than any other discipline in science," Päs writes. And yet "it doesn't tell the full story. Because if we pay attention to the full story, we will see that particles do not compose the world; it is the other way around."Basic Books

The word universe actually means all things cohered into one. Isn’t this idea already staring us in the face?

Yes, yes, it is. But still, when we think of the universe, we think of many planets, many stars, parallel realities, maybe — a vast thing made out of many, many little things.

And so if someone were to say, “How many things are there in the universe?” the real answer, you say, is not “I don’t know — trillions upon trillions of things.” It’s one thing.

Yes.

What are the implications for physics? Should this recalibrate expectations for what hugely expensive and complicated particle accelerators could ever possibly reveal?

Yes. I mean, I’m not against particle accelerators. They have done great things in the past, but I think this idea that the farther we go to smaller distances and higher energies, the more we come to the fundamental truth — this at some point will not work anymore. We will have to realize at some point that smaller doesn’t mean more fundamental anymore. At some point, this quantum effect of entanglement kicks in and the most fundamental thing is the entire universe.