Science Can’t Explain Everything

Hello, friends!

As you know, I love science.  I’m a little obsessed.  But there are people who get annoyed or even offended by my obsession with science, and every once in a while one of these people will remind me, sternly, that science can’t explain everything.  And you know what?  I generally agree with that sentiment.  But then people start declaring that science will never know this specific thing or that specific thing, and I immediately think of a certain 19th Century French philosopher named Auguste Comte.

Comte was not some scientifically illiterate buffoon.  He wasn’t one of those 19th Century evolution deniers, or one of those latter-day opponents to the heliocentric model of the Solar System.  In fact, Comte is regarded today as the very first philosopher of science, in the modern sense of that term, and he gets credit for coining the word “sociology” and for laying the philosophical foundation for that entire branch of science.  There’s also a wonderful quote from Comte about the mutual dependence of scientific theory and scientific observation.  Basically, you can’t formulate a theory without observation, but you also can’t make an observation without the guidance of a theory.

But that is not the Comte quote I think of whenever somebody starts lecturing me about the things science will never know.  It’s this quote about the stars: “[…] we shall never be able by any means to study their chemical composition or their mineralogical structure…”  Comte also declared that: “I regard any notion concerning the true mean temperature of the various stars as forever denied to us.”

Comte wrote this in 1835, and if you can put yourself into an 1835 mindset you can see where he was coming from.  There’s no such thing as rocketry.  We don’t even have airplanes yet.  And even if you could fly up to a star (or the Sun), how would you measure its temperature?  What kind of thermometer would you use?  And how would you go about collecting stellar material, in order to determine the star’s chemical composition?

According to Comte—a highly intelligent and very pro-science person—this sort of knowledge was utterly impossible to obtain.  And yet only a few decades later, thanks to the invention of the spectroscope, scientists started obtaining some of this unobtainable knowledge.  For those of you who don’t know, spectroscopes separate light into a spectrum.  Some parts of the spectrum may appear brighter or darker than you might otherwise expect, depending on which chemical substances emitted or absorbed the light before it reached the spectroscope.  And so by comparing the spectral lines of chemicals we have here on Earth to the spectrum obtained from the light of a star, you can determine the chemical composition of that star.

You can also measure a star’s temperature thanks to a concept known as black body radiation.  Basically, black body radiation refers to the fact that things glow as they got hotter.  If no other light sources are involved, then the color of a glowing object will be directly related to that object’s temperature.  Ergo, if you know what color a star is, then you can work out a pretty accurate estimate of what temperature that star must be.

Auguste Comte didn’t foresee any of this.  It is certainly true that science does not know everything, and there are surely things that science will never know.  But if you think you know, specifically, what science can never know, I question that.  Someday, some new invention (like the spectroscope) or some breakthrough discovery (like black body radiation) may turn an utterly unknowable thing into a matter of trivial measurements and calculations.

Maybe the one thing science truly can never know is what science’s own limitations are.


Here’s a very brief post about Auguste Comte, what he said about stars, and how epically wrong he was with that one prediction.

Also, here’s a short article about some genuine limitations that science has, like aesthetics, moral judgements, etc.

Sciency Words: Hydrogen

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we talk about the definitions and etymologies of scientific names and terms.  In today’s episode of Sciency Words, we’re talking about:


I want to start this with a personal story.  Imagine me, twenty years ago, fresh out of college with a degree in television and film production.  One of my first jobs was working for a company that made educational cartoons for children.  At one point, I ended up being assigned to a two minute animated music video about water.  The name of the video: “Water Can Never Be New.”

Now I’m no scientist.  I cannot call myself an expert (I’m just very enthusiastic about this subject).  And twenty years ago, I was even less of an expert than I am today.  Still, even way back then, I had a nagging suspicion that this “Water Can Never Be New” video was a lie.  Which brings me to the subject of today’s post: hydrogen.

Definition of hydrogen: Hydrogen is the very first element on the periodic table of elements.  Typically, hydrogen atoms consist of one proton orbited by one electron.  Molecular hydrogen consists of two hydrogen atoms bonded to each other.  Under Earth-like temperatures and Earth-like atmospheric pressure, hydrogen is a gas.  It’s also rather rare here on Earth; elsewhere in the universe, it’s extremely common.  In fact, hydrogen is by far the most common, most abundant chemical element in the universe.

Etymology of hydrogen: Hydrogen was first discovered in 1671 by British natural philosopher Robert Boyle.  Boyle referred to this new kind of air he discovered as “inflammable air,” because of how easily he could light it on fire.  Over a century later, French chemist Antoine Lavoisier found that burning “inflammable air” somehow produced water vapor as a byproduct.  Thus, Lavoisier changed the name of “inflammable air” to hydrogen, from two Greek words meaning “water” and “creation.”

It’s hard to imagine today just how much the discovery of hydrogen must have rocked the world of science (a.k.a. natural philosophy) back in the 17th and 18th Centuries.  Up until that point, the Aristotelian view of world had prevailed.  According to Aristotle, four elements—fire, earth, air, and water—were the fundamental building blocks of nature.  Then Robert Boyle comes along with a new kind of air (can we really call air a fundamental element if there are different kinds of it?), and Lavoisier subsequently demonstrates that you can use this new kind of air to make water (is water really a fundamental element if you can make it out of other stuff?).

Today, we know more about what happens when you light hydrogen gas on fire.  The heat energy from the flame causes hydrogen to react with oxygen, producing H2O molecules.  Water, in other words.  New water.  And, in fact, many chemical reactions involving hydrogen and oxygen-containing compounds will produce water molecules as a byproduct.  Due to the energy involved in these reactions, this new water may be too hot to form a liquid, but water vapor is still water (and it will condense into a liquid eventually, once it has time to cool off).

Of course, hydrogen does much more than help make new water molecules.  Hydrogen is the fuel that keeps the Sun shining.  It’s a necessary component in the organic compounds that make life as we know it possible, and hydrogen ions play an important role in acid-base chemistry (not counting Lewis acids and bases).  Given the wide variety of jobs that hydrogen does, you may wonder why we stick to using a name that means, simply, “water generator.”

But the discovery of hydrogen and its water generating ability helped upend some deeply entrenched and woefully inaccurate scientific ideas.  The name seems appropriate to me as a way to honor that moment in the history of science when the old Aristotelian view of nature really started to crumble.  It’s a shame more people don’t know about this story.  Maybe somebody should make an educational cartoon for children about it.