What is fire?

No definition is perfectly concise. We associate words with images and pretend that we all agree on their meaning, but we are occasionally reminded that we don’t always agree. I remember, as a child, being surprised to hear that school buses are yellow, having been of the opinion that school buses are orange.

“Fire” is a particularly difficult word to corner. It is generally associated with the chemical process of rapid combustion, a chain reaction of oxidation reactions in a gas. This “fire” occurs in hearths, automobile engines, forests, and volcanoes.

I think we can safely agree that all such rapid oxidation events can be called “fire,” but one other phenomenon is very fire-like, though it has nothing to do with oxidation. It is the fire that we see burning on the sun. It is sometimes called stellar fire, stellar combustion, or astrophysical combustion. I’ve heard educated people say “the sun isn’t really a fire,” because they identify the word with chemical combustion, but the word is much older than combustion theory, which was first presented in 1777, a year after the American Declaration of Independence.

What is combustion? According to modern chemistry, it’s an electron transfer, but it’s called “combustion” because of its macroscopic character as an exothermic chain reaction. The word was not chosen because of any association with electron transfer, but because of its association with the phenomenon we have called fire since the Greeks called it “pyr”. The Latin root of combustion is a word that means “burning.”

What about fire leads us to call it fire? What are its characteristics—its phenomenology?

To understand the phenomenology of combustion, it helps to bear in mind that flames only occur in the presence of a gas, and that gas will not ignite without adequate heat. What is a hot gas? At the molecular level, a hot gas is just a cloud of accelerated molecules. It is the kinetic energy of free molecules colliding with each other that makes combustion possible. Molecules are broken apart in the melee, and the fragments recombine to form new molecules, often generating free electrons that will start further combustion reactions. The result of this chain reaction is a burning gas that we call “fire” and chemists call “rapid combustion.”

But how different is this chain reaction from what goes on in the sun? Sure, we know that the solar fire is driven by fusion reactions rather than molecular bonding, but that aside, we still have a chain reaction in a dense “cloud” of high energy objects breaking apart, forming new objects, and releasing light and heat. In both cases, we have a bright, circulating mass of convection, conduction, and radiation. Both phenomena are self-sustaining and self-replicating, so long as fuel is available. Given that the word “fire” predates our discovery of either molecular combustion or atomic fusion, it seems hasty to attach it to the former while keeping it at a safe distance from the latter.

Now that we can recognize the kinship of these exothermic, self-sustaining, self-replicating chain reactions as species of fire, we might consider what other processes can be recognized with similar characteristics. One obvious example occurs to me: life.

In what ways is life like a fire?

Pub Skeptics Update

I didn’t bother to post an announcement here for the March Skeptics in the Pub event. Another announcement really wasn’t needed. An estimated twenty skeptics showed up at O’Flaherty’s (that’s a record!), and the conversation was—I daresay—even better than the beer. Next month: the world!

Skeptics in the Pub, Part Deux

It’s time for South Bay skeptics to gather at the pub again! Since last month’s get-together at O’Flaherty’s in San Jose went so well, we’ll be meeting there again tonight. We have fifteen freethinkers signed up to show up tonight (a veritable convention).

An Agenda

Just in case this “informal forum” doesn’t lift itself up by its own bootstraps, I’m offering up the following framework:

1. Personal Introductions

  • Personal Background (and how it inspired the skeptic in you)
  • Favorite Self-Label: skeptic? atheist? freethinker? contrarian? drunk?
  • Favorite Topics: religion, pseudoscience, alternative medicine, climate change, etc.

2. In the News

Scientology: in the FBI’s crosshairs?


Bacterial Intelligence

3. Hot Topics

Topics recently covered by noted skeptics



Climate Change


Related Links

Skeptics in the Pub

I’ve been meaning to start a local get-together for South Bay skeptics for some time now. Since nobody seems to be in a hurry to beat me to it, here goes.

Let’s start with O’Flaherty’s in San Jose, it being about as close a thing to a pub as we have in the South Bay. If the meet is successful enough to render O’Flaherty’s too cozy, we can move ourselves accordingly.

An Agenda

Just in case this “informal forum” doesn’t lift itself up by its own bootstraps, I’m offering up the following framework:

1. Personal Introductions

  • Personal Background (and how it inspired the skeptic in you)
  • Favorite Self-Label: skeptic? atheist? freethinker? contrarian? drunk?
  • Favorite Topics: religion, pseudoscience, alternative medicine, climate change, etc.

2. In the News

Astrology in Crisis, by Steven Novella (Jan 18)

Sign of the Times: Astrology story soars like a comet, StarTribune.com (Jan 14)

Murder, Mass Die Offs, and the Meaning of Randomness, Michael Shermer (Jan 12)

Gun violence and bird die-offs in America

Pakistan rally backs blasphemy law — Al-Jazeera (Jan 9)

Deadly warning to Pakistan liberals — Al-Jazeera (Jan 7)

3. Hot Topics

Topics recently covered by noted skeptics

TestabilitySkeptics Guide 5×5 #100 (Jan 13)

  • Falsifiability: necessary but not sufficient
  • Can it be used to make predictions?
  • Some claims are non-falsifiabile by design (e.g. the claim that the earth was created to look like it’s billions of years old)
  • “The Big Bang theory … was once considered untestable”
  • The distinction between scientific and unscientific can be fuzzy (e.g. string theory)
  • Carl Sagan’s invisible floating dragon that breathes heatless fire.
  • Untestable propositions aren’t necessarily wrong; merely outside the domain of science.

Repressed Memories: Skeptics Guide 5×5 #97 (Dec 20)

You just think we’ve never met. You’re just repressing me, that’s all.

Mystery Spots: Skeptoid #240 (Jan 11)

Patronized your local gravitational anomaly lately?

Gluten Free Diets: Skeptoid #239 (Jan 4)

Is bread making you sick?

Related Links

The Fool and the Prince

Once upon a time, in a land not so far away, there lived a fisherman’s son. He was not favored by the girls of the village, for he was neither smart nor good looking. He was such a fool; in fact, that the village folk got much pleasure at his expense, for he in his foolishness had given them many a humorous anecdote. Many of them would reflect that the boy had once, not very long ago, caused a great uproar of laughter when a royal procession had passed through the village. The boy had invited the crown princess to take lunch with him! Not only had the village folk broken out in laughter (many of them injuring themselves by laughing too hard), but the boy had been compelled to flee for his life when two of the royal guards tried to arrest him for his impertinent mouth. Lucky for the foolish boy, he leaped into the harbor before the guards could grab him, and he hid beneath the dock until the guards were ordered to proceed.

Continue reading

Cannibal Planet

It sometimes seems to me that eating fellow vertebrates is a degree of cannibalism, for we do share very much with our fellow vertebrates in the way of anatomy and natural intelligence, and when it comes to dining on fellow mammals—all the more.

Cannibals? who is not a cannibal? I tell you it will be more tolerable for the Fejee that salted down a lean missionary in his cellar against a coming famine; it will be more tolerable for that provident Fejee, I say, in the day of judgment, than for thee, civilized and enlightened gourmand, who nailest geese to the ground and feastest on their bloated livers in thy paté-de-foie-gras.

Ishmael, Moby Dick

The consumption of alien beings such as octopi also seems a degree of cannibalism since they too share a degree of intelligence with us, though their intelligence is quite alien to ours.

The Hungriness of Stuff

We previously reflected upon the intimate, multifaceted relationship between ancient man and fire, and considered how easy it would have been for a man such as Heraclitus to conceive of the idea that fire is the fundamental constituent of all matter.

Heraclitus was, after all, a subject of the Persian Empire, a land of fire worship, and the reputed cradle of alchemy. Alchemy is a practice of transmuting matter that depends greatly upon fire. It seems to be a natural—albeit mystical—offspring of the bronze age.

Perhaps after recognizing the ubiquity of fire, Heraclitus reflected upon the nature of fire, and came to this conclusion:

Burning Man effigy, Black Rock City, Nevada

Burning Man effigy, Black Rock City, Nevada

fire is hunger and satiety.


Fire is indeed a hungry phenomenon. It seems to exist exclusively to consume, though the light and heat it has provided us through the millennia make it much more than a consumer. Yet it remains an archetype of consumption. Is not combustion the primal hunger within us? Is it not our deepest physiological craving for the fuels of combustion: oxygen and carbon compounds?

But fire is obviously not equal to hunger, for as consumption, it is also the satisfaction of its hunger.

Seeing everything around us as governed by this paradox, one can easily see the function of fire in the philosophy of Heraclitus. Heraclitus taught that the world is governed by a harmony of opposites. Recognizing that harmony, he saw wisdom in the working of things, but it was a harmony of war, of hunger. Whatever equilibrium he could see was a dynamic, cyclic equilibrium under tension. To Heraclitus, fire must have seemed fundamental both literally and metaphorically.

Fire and Water

Here in California, we have two seasons: a season of water and a season of fire. The fire season generally begins when the rains cease, which is typically in mid-April—say, Tax Day. The fire season continues beyond the end of summer into the warm California autumn, until the rains return—around about Halloween.

I remember, as a matter of fact, the rains returning last Halloween, while trick-or-treating with the kids. I remember how warm that first rain was. It even seemed refreshing.

The old Gaelic year ended on Halloween, so I hear. In California, the return of the rains is obviously a big deal, but I’m not sure it ought to mark our new year (as though it represented a rebirth).

I say I’m not sure, but it probably should. It’s ironic because the leaves haven’t even fallen from the trees yet by Halloween, but one can watch the world being slowly reborn through the mild winter months. February and March bring progressively more glory, but it all begins with the first rain in autumn.

My doubt has to do with the role of the sun in all this. To base the rebirth solely upon the return of the rains seems to disrespect the importance of sunlight in bringing about life, but I suppose it’s obvious enough that this is all made possible by the fact that the sun is somewhat ever-present around here.

Pink Floyd and Thoreau

I was just listening to the Pink Floyd song “Time” the other day, when three lines of the song struck me:

You fritter and waste the hours in an off hand way …
You are young and life is long and there is time to kill today …
Hanging on in quiet desperation is the English way

I had long been cognizant of a connection between the last line and something Henry David Thoreau wrote in Walden:

The mass of men lead lives of quiet desperation

… but this time I suddenly recognized two other connections between this song and Thoreau’s masterpeice:

Our life is frittered away by detail … Smplify, simplify.

as if you could kill time without injuring eternity.

I wonder what Roger and the boys had been reading when they wrote “Time”. Though I don’t see the same depth in the song that can be found in Walden, these verbal coincidences make me wonder what were their inspirations.

The Source

The theme, or motto, of this blog has its source in an essay of Plutarch entitled “On Listening to Lectures.” Here’s a translation of Plutarch’s actual words:

The correct analogy for the mind is not a vessel that needs filling, but wood that needs igniting — no more — and then it motivates one towards originality and instills the desire for truth.