Is the Universe Really “Getting Smarter”? An Analysis of the Scientific Debate Behind “The Second Arrow of Time”
Hello everyone, I’m your financial journalist and economist. Today, we’re going to talk about a book that might sound a bit esoteric at first glance—“The Second Arrow of Time”—but its core question is actually quite practical: Why is the world becoming more complex, rather than more chaotic?
Let’s use an analogy to explain. When you scatter sand, it lands in a messy pile (disorder). However, if you combine sand, cement, and steel according to a plan, you end up with a building (order). Physics tells us that the general trend of the universe is “entropy increase,” which means moving from order to disorder—just like how new shoes wear out and leaves decay.
But look at the universe itself: from the simple gases after the Big Bang, to the carbon and oxygen produced within stars, to the intelligent human brain that has evolved on Earth. That’s clearly a case of moving from disorder to order!
Two scientists from the Carnegie Institution of Science, Robert Hossen and Michael Huang, propose in their book that there might be a new natural law at work, which they call the “Law of Increasing Functional Information.” In simple terms, useful structures are preserved, leading to increasingly complex systems.**
This book, with fewer than 200 pages, has sparked a major scientific debate. I’ll break down this debate about the fate of the universe for you in five key points.
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1. The Core Idea: Even Stones Evolve; the Universe May Be “Self-Assembling”
First, we need to understand what the authors are suggesting.
We usually think of evolution as something that happens to living things, like how dinosaurs turned into birds or monkeys into humans. But Hossen and Huang argue that even stones evolve.
- Evidence from Minerals: When the universe was born, there was only one type of mineral (diamond). Over time, stellar explosions recombined elements, creating 25 new minerals. On Earth, the number of minerals has grown to more than 6,000.
- The Logic of Selection: Not all mineral combinations can exist stably. Most fall apart upon contact, but only those with stable structures that can withstand environmental pressures survive.
- Conclusion: This process of survival of the fittest is called “natural selection” in biology and “stability selection” in minerals. The authors believe that any system that meets three conditions—many possible combinations, the generation of new combinations, and a selection mechanism—will spontaneously become more complex and functional.
In simple terms: It’s like shopping online; although there are countless products, only the good-quality, cost-effective ones will be purchased and remain on the shelves. The authors suggest that the universe is like a giant e-commerce platform, becoming more organized through this process of selection.
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2. Theoretical Foundation: What Does “Functional Information” Measure?
To prove that the universe is becoming more complex, we need a way to measure complexity or order. The authors use a concept called “functional information,” coined by Nobel Prize winner Jack Szostak.
- An Example: Imagine you’re looking for a key to open a specific lock. If any key will do, the lock has low functional information (it’s too easy to use). If only one key out of a billion works, it has high functional information (it stood out among countless possibilities).
- In Science: Szostak found that as RNA fragments were filtered in experiments, those with specific functions became rarer, but their functional information increased.
- In Minerals: Hossen’s team argues that the functional information of minerals has increased over time. Later minerals are more “unique” and “precious” in terms of stability.
- Key Point: The authors believe this increase in functional information is not random but inevitable. They call this the “second arrow” of time—while the second law of thermodynamics (entropy increase) is the first arrow pointing to the passage of time, functional information increase points to complexity and order.
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3. Internal Contradictions: Why Are Two Opposing Theories Fighting?
The scientific community has long debated how order can emerge from entropy increase. Previously, it was thought that local order was not surprising as long as energy was supplied (as suggested by Schrödinger and Prigogine). Hossen and Huang want to establish a new law.
However, within this camp, there’s another group proposing the “Assemblage Theory” (by Lee Cronin and Sarah Walker).
- Assemblage Theory: This theory uses an “assemblage index” to measure complexity, i.e., the minimum number of steps needed to form something from its parts. More steps indicate complexity, which might be a sign of life.
- Why the Debate?
- Hossen’s Criticism: Some non-living minerals (like stones) have high assemblage indices, similar to biological molecules. If we use the Assemblage Theory, does that mean stones are life? That’s absurd. So, the Assemblage Theory can’t be the sole criterion for life.
- Walker’s Counterargument: How do you measure functional information? What defines the “function” of a stone? If there’s no objective method, the theory can’t be tested and thus isn’t scientific.
- In Simple Terms: It’s like two chefs creating new recipes. Hossen says his recipe explains how both stones and life become complex; Walker says his recipe is unquantifiable and impractical, while hers is precise.
- The Debate: This debate is crucial for determining how we will search for extraterrestrial life.
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4. External Criticisms: Is This a “New Law” or Just Reusing Old Concepts?
Besides internal disputes, there are external criticisms:
1. Redundancy Theory (Algorithms and Information Theory): Hector Zehner argues that the observed increase in functional information was already predicted by computer algorithms. Simple, modular structures are more likely to form, so it’s not a new physical law but a mathematical consequence. There’s no need for a new law.
2. Immeasurability (Experimental Approach): Walker points out that we can’t even calculate the functional information of a living cell, so how can it be a universal law? Hossen admits that functional information is difficult to calculate for most physical objects.
- Rebuttal: We couldn’t calculate the dynamics of the asteroid belt accurately before, but approximate descriptions were enough for spacecraft missions. The lack of precise values doesn’t mean the theory is useless.
3. Self-Contradiction (Logic): *Publishers Weekly* notes that the authors say laws must predict the future, but their theory can only explain the past (the increase in minerals). It’s like a doctor saying you’re sick due to bacteria but unable to predict your recovery.
- Supporters’ View: Despite these criticisms, *The Kirkus Review* calls it a “paradigm-shifting work.” Professor Kaufman of the University of Pennsylvania believes the book makes the question of whether the universe is becoming more orderly relevant and important. Physics spent centuries rejecting purposefulness; introducing “function” is a significant shift in thought.
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5. The Ultimate Test: The Dragonfly Probe to Saturn
Is there a way to settle this debate? The authors mention a specific experiment: NASA’s Titan probe.
- Goal: To study the surface and atmosphere of Titan, a moon of Saturn.
- Potential Proof: If the Law of Increasing Functional Information is true, the probe should detect a trend of increasing functional information over time, independent of the observer’s choices.
- If Proven: The “second arrow” would become a physical fact, showing that complexity and intelligence are universal, and we’re not alone in the universe.
- If Not Proven: The theory might remain just another useful metaphor, not included in textbooks.
- Historical Context: The concept of entropy didn’t exist until Clausius defined it in 1865. The second law of thermodynamics also went through a similar phase. The lack of precise measurement doesn’t necessarily mean the theory is wrong; it just lacked a measurable standard.
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Conclusion: Are We Alone in the Universe?
The main contribution of this book is not a definitive answer but a shift in how we ask the question.
- Past Questions: Does complexity violate the second law of thermodynamics? (No; local order is not contradictory.)
- Current Question: Is complexity a separate, inevitable aspect of the second law?
If Hossen and Huang are right, the universe is not just moving towards thermal death (complete chaos) but also towards functional complexity. This suggests that intelligent life like ours might not be an exception but a natural outcome of this “second arrow.”
For us, the significance of this book is that it makes us reevaluate the value of order. In a world of apparent chaos and increasing entropy, useful and stable structures are preserved by nature. Whether it’s minerals, RNA, or civilizations, as long as you show unique functionality, you could be part of this process of becoming more complex.
The final answer will come when the Titan probe returns data from Saturn. Until then, this remains a fascinating, controversial, yet highly enlightening scientific speculation.