Tag Archives: Universe

A Guide to Reality, Part 4

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Chapter 2 of The Atheist’s Guide to Reality is probably the key chapter in the book. That’s where Professor Rosenberg lays out his view of physics and the nature of reality. He doesn’t mince words:

Everything in the universe is made up of the stuff that physics tells us fills up space, including the spaces that we fill up. And physics can tell us how everything in the universe works, in principle and in practice, better than anything else. Physics catalogs all the basic kinds of things that there are and all the things that can happen to them (21).

According to Rosenberg, “we should embrace physics as the whole truth about reality”. Why? Because science is a cumulative process, in which findings are confirmed, corrected or refuted, resulting in a solid foundation. Physicists are still learning things, but the “part of [physics] that explains almost everything in the universe – including us – is finished, and much of it has been finished for a century or more” (21).

Physicists, in particular, have discovered that everything in the universe is composed of either fermions (such as quarks, electrons and neutrinos) and bosons (like photons and gluons), and combinations thereof (like protons and molecules). Fermions are usually associated with matter, while bosons are usually associated with fields and forces. Rosenberg says that’s all there is:

All the processes in the universe, from atomic to bodily to mental, are purely physical processes involving fermions and bosons interacting with one another…Physical theory explains and predicts almost everything to inconceivably precise values over the entire body of data available…From a small number of laws, physics can neatly explain the whole trajectory of the universe and everything in it…The phenomenal accuracy of its prediction, the unimaginable power of its technological application, and the breathtaking extent and detail of its explanations are powerful reasons to believe that physics is the whole truth about reality (21-25).

But what about the other sciences? Surely, chemistry and biology, for example, say something true about reality. Rosenberg, however, argues that physics explains chemistry and chemistry explains biology. Everything that happens in your body is a chemical process, and every chemical process is a physical process:

The only causes in the universe are physical, and everything in the universe that has a cause has a physical cause. In fact, we can go further and confidently assert that the physical facts fix all the facts … including the chemical, biological, psychological, social, economic, political and other human facts (25-26).

He left out the geological and cosmological, but you get the idea. Higher-level sciences are in principle reducible to lower-level sciences. Philosophers call this view “reductionism”. Rosenberg is clearly a “reductionist” of some sort. A similar claim is that all higher-level facts depend or “supervene” on lower-level facts (this principle is called “supervenience”). Rosenberg asks us to imagine two regions of space-time, our own plus another millions of light-years away, in which every fermion and boson is arranged exactly the same way. In such a case, everything else in the two regions would be the same too. Regardless of the regions’ respective histories, if all the sub-atomic particles are arranged the same way, the two regions will contain the same rocks, the same birds and bees, the same political institutions, the same music, the same people with the same memories and thoughts. Physics fixes all the facts.

Next time, before continuing with chapter 2, we’ll consider whether it’s reasonable to “embrace physics as the whole truth about reality”.

A Guide to Reality, Part 3

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Continuing to work through The Atheist’s Guide to Reality by Alex Rosenberg:

Professor Rosenberg begins chapter 1 by explaining why he’s not going to spend much time arguing for atheism: others, especially David Hume, have already done that quite well; such arguments, even very good ones, don’t convince true believers; and anyway, it’s more important to understand how science can help us live without illusions than to keep talking about religion.

Instead, Rosenberg is going to discuss a view called “scientism”. As he notes, “scientism” is usually applied in a negative way to people who supposedly worship science, or try to extend it beyond its natural borders, or simply take it too seriously. Rosenberg welcomes the term, defining it this way:

[Scientism] is the conviction that the methods of science are the only reliable ways to secure knowledge of anything; that science’s description of the world is correct in its fundamentals; and that when “complete”, what science tells us will not be surprisingly different from what it tells us today (6-7).

The idea that the current scientific description of the word is fundamentally accurate is known among philosophers as “scientific realism”. The Stanford Encyclopedia of Philosophy defines it as “a positive epistemic attitude towards the content of our best [scientific] theories and models, recommending belief in both observable and unobservable aspects of the world described by the sciences”. In other words, science is a highly reliable way to acquire knowledge of the world. Science allows us to learn about the world as it is, independent of our minds. Science even allows us to find out about things we can’t directly observe, like the Big Bang and sub-atomic particles.

Rosenberg is clearly a scientific realist. Not all philosophers are (they, in fact, disagree to some extent about what science is). But Rosenberg’s scientism goes beyond simple scientific realism when he asserts that “the methods of science are the only reliable ways to secure knowledge of anything”.

Maybe he’s exaggerating on purpose (not something philosophers ordinarily do), but are you and I doing science when we look out the window and agree that it’s snowing? Is a student doing science when she concludes that Socrates was mortal if Socrates was a man and all men are mortal? As Rosenberg knows, of course, science relies on occasionally unreliable activities like seeing and hearing in order to gather evidence. Even though scientists don’t rely on a single person’s observations, they do use the same perceptual abilities the rest of us employ to acquire knowledge. In addition, most of us would agree that people clearly know lots of things that aren’t “scientific” in the usual sense (including math, logic, historical facts, cultural practices and whether the Ford is in the driveway).

Perhaps it’s enough that an adherent of scientism believes that, when applied correctly, the various methods of science are by far the best ways we have to get at the truth about many or most features of the world. Those methods include classification, observation, experimentation, measurement, replication, discussion, publication and other things physicists, chemists, biologists and psychologists regularly do.That seems right to me, but I don’t think it’s enough for Rosenberg.

Before moving on, I should mention that Rosenberg also considers this question: if science is such a reliable method of determining the truth, why do so many people reject scientific conclusions? One reason, of course, is that scientific results are often revised. Another is that scientists often disagree among themselves, especially on topics that make the news, in some cases because they are influenced by un-scientific factors, like working for Exxon. Yet another big reason why many are skeptical about science is that scientific conclusions often make people uncomfortable (as in the case of climate change, for example).

Rosenberg, however, mainly discusses the human need for “stories”, by which he means our tendency to understand the world in terms of personalities and purposes. He argues that our ancestors became good at recognizing and interpreting purposeful behavior because that skill made it much easier to live and prosper among other people. Evolution, however, overshot the mark. People heard thunder and concluded that Someone was angry. Today, according to Rosenberg, people have trouble understanding math and physics because their subject matter doesn’t include human beings or other creatures doing things. In other words, science is especially hard because most people haven’t been built (through evolution) to understand it. Religion, on the other hand, often involves stories, which we generally find more easy to understand than science.

In the next installment: physics and the nature of reality.

Cosmic Justice

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According to the Detroit News, a 19-year old black woman, Renisha McBride, had a car accident in the predominantly white suburb of Dearborn Heights, Michigan, at around 2:30 a.m. on Saturday morning. Her cell phone battery was dead, so she began looking for help. After knocking on the door or ringing the bell at a house on Outer Drive, she was shot in the head and killed. The Dearborn Heights police department found her body on the front porch. They know who killed her but haven’t released the person’s name.

Michigan is one of the states that now has a “Stand Your Ground” law. Michigan’s law says that a person has the right to use deadly force against another person if he or she “reasonably” believes such force is necessary to protect himself, herself or someone else from imminent death, great bodily harm or sexual assault. Given the facts reported so far, asking the woman ringing your door bell at 2:30 a.m. what she wanted or calling 911 would have been more reasonable than putting a bullet through her head. The incident is now in the hands of the Wayne County prosecutor.

In news that could be related, physicists have discovered that the Higgs field, what the New York Times calls “an invisible ocean of energy that permeates space, confers mass on elementary particles and gives elementary forces their distinct features and strengths” might undergo a phase transition resulting from a random quantum-level fluctuation. This phase transition would make the Higgs field much denser than it is now. That change would destroy everything in the universe more complex than hydrogen, the simplest element there is. 

In fact, a random fluctuation of this kind might have already occurred, meaning that the resulting phase transition (in effect, a wave of destruction traveling at the speed of light) might be heading for us right now. We won’t know if it’s coming or notice if it arrives: “the idea is that the Higgs field could someday twitch and drop to a lower energy state, like water freezing into ice, thereby obliterating the workings of reality as we know it”.

It would be as if Someone finally got fed up and turned off the cosmic switch that controls everything around us, including Dearborn Heights, Michigan.

Fortunately or unfortunately, depending on your view of cosmic justice, it is very, very unlikely that the Higgs field will change any time soon. Nevertheless, it could happen, especially if Someone gets really fed up.

Update:  Apparently, it was a man who killed Renisha McBride. He did it with a shotgun and says it was an accident. He also says he thought she was an intruder (the kind who knocks on the front door or rings the bell?).  

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The death of Renisha McBride:  http://www.detroitnews.com/article/20131105/METRO01

The Higgs field: http://www.nytimes.com/2013/11/05/science/finding-the-higgs-leads-to-more-puzzles

A nice, 14-minute video that explains how very unlikely it is that the lights will go out while we’re still around: http://www.ted.com/talks/why_our_universe_might_exist_on_a_knife_edge

Why It’s So Quiet Out There

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Many of us fondly remember Carl Sagan proclaiming on television that there are billions and billions of stars in the universe. So much for memory, because it was Johnny Carson and his fellow comedians who spoke the phrase “billions and billions” when they did their impressions of the professor. Sagan often said “billion” and “billions” in his Cosmos program, but the closest he ever came to saying “billions and billions” was apparently this:

There are in fact 100 billion galaxies, each of which contain something like a 100 billion stars. Think of how many stars, and planets, and kinds of life there may be in this vast and awesome universe…. We find that we live on an insignificant planet, of a humdrum star, lost in a galaxy, tucked away in some forgotten corner of a universe, in which there are far more galaxies than people.

But if there are billions and billions of stars and who knows how many planets, why is the universe so quiet? Shouldn’t we detect some signals from other worlds?

Part of the answer is that radio waves and similar signals get weaker the farther they travel. An inhabited planet would have to be fairly close to Earth, maybe less than ten light-years away, for us to distinguish its version of “I Love Lucy” or its “anyone out there?” message from the general cosmic noise.

And, despite a new report in the Proceedings of the National Academy of Sciences, there may not be a terrifically large number of habitable planets in our galaxy (the nearest stand-alone galaxy is two million light years from the Milky Way, so those billions and billions of other galaxies aren’t really relevant to the discussion).

The science academy report says there are (depending on which news story you read) between nine and forty billion planets in the Milky Way similar to Earth. In this case, “similar” means having about the same mass as Earth and being at the right distance from their respective suns to have liquid water on their surface. Whether it’s nine billion or forty billion, it seems like a pretty big number, so articles in the news media are generally implying that we probably aren’t alone.

On the other hand, the galaxy is a very big place and life may be extremely rare. If the odds against life coming into existence on an Earth-like planet and then evolving into something like us are one billion to one, there are now between nine and forty planets in the galaxy capable of producing situation comedies. It would be very odd if any of them were close enough for us to notice. In this context, therefore, forty billion would be a rather small number.  

Maybe we aren’t completely alone in the universe, but even with these new findings, we should get used to the idea that we’re stuck with each other (and make the best of it).

Update: A physicist wonders about the likelihood of life coming into existence. We don’t know what the odds are:

…if life arose simply by the accumulation of many specific chemical accidents in one place, it is easy to imagine that only one in, say, a trillion trillion habitable planets would ever host such a dream run. Set against a number that big — and once you decide a series of unlikely accidents is behind the creation of life, you get enormous odds very easily — it is irrelevant whether the Milky Way contains 40 billion habitable planets or just a handful. Forty billion makes hardly a dent in a trillion trillion.

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One of the news stories:

http://www.nytimes.com/2013/11/05/science/cosmic-census-finds-billions-of-planets-that-could-be-like-earth.html

What Carl Sagan had to say:

What Made the Big Bang Bang?

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Physicists believe our universe began with a “Big Bang” about 14 billion years ago. The evidence suggests that the universe was infinitely hot and infinitely dense before it rapidly expanded, resulting in the still-expanding universe of which we are a tiny part.

But the physicists don’t know why the Big Bang occurred or what, if anything, existed before it. Maybe an earlier universe collapsed upon itself and then bounced back in a tremendous explosion. Maybe our universe resulted from some kind of random quantum fluctuation — or from a really cool experiment carried out by a kid with blue skin and 12 eyes.

Another hypothesis, of course, is that God kicked off the Big Bang. I wouldn’t bet on that, but you never know (although you might get to know if you ever join the choir invisible).

It’s also been suggested by some physicists that a black hole in another universe may have had something to do with the beginning of ours. The latest theory along those lines is that a star in a universe with four spatial dimensions (not our familiar three) ended its life as a supernova, creating a 4-D black hole at its core and simultaneously ejecting some debris out into 4-D space. Our universe could be a 3-D sliver of this 4-D cosmic debris. Or something like that.

Something immediately struck me when I read an article about this latest theory. It wasn’t the plausibility of the theory, which I’m almost completely unqualified to judge. It was the sudden feeling that we’ve now figured out why the Big Bang occurred. And no god had anything to do with it! It’s just the cosmos and us after all!

If I were religious, this momentary reaction might be understandable. But I’m not. So why did the idea that there’s no god out there pulling strings make me feel suddenly lonely? I guess it’s hard to escape your upbringing, no matter how old you get. And all that space out there can make a person feel a little bit alone, even on a planet with 7 billion people and 3 billion internet users.

Of course, God could have created that other universe that gave rise to ours, or the even earlier universe that gave rise to that one, or the one that came before that other one, and so on and so on, but somehow it’s just not the same once universes start giving birth to new ones all by themselves. 

http://www.nature.com/news/did-a-hyper-black-hole-spawn-the-universe-1.13743