Science and Faith

I’m often asked by my non-scientist friends about how physics informs my faith.  (Funny, my scientist friends never raise this kind of question.)

Short answer: it doesn’t.  Long answer: it’s complicated.

I see physics a collection of models and concepts used to explain and predict the behavior of well-defined systems.  A good example is the weather.  It’s a fantastically difficult physics problem, but it makes a good illustration.  You start with a model of the Earth’s atmosphere.   The model exists as a set of equations that summarize various physical relationships.  You add in some data: current temperature, barometric pressure, wind velocity, etc.  The model, through a computer program, calculates future values of those parameters.  The forecast is evaluated by comparing it to the real weather.  If the forecast is close to the real weather, the model is good.  If not, something’s wrong with it.

What could be wrong requires a lot of discussion.  Briefly, the input data could be bad, or the model may not be detailed enough.  Or, perhaps the model is based on faulty physical concepts.  For example, when Newton’s law of universal gravitation fails to correctly predict the fine details of Mercury’s orbit, it’s because the model has a built-in conceptual error.  (Physics majors will know the error, maybe.  Let us know in the comments if you think you’ve got it.)

Physical models by their very nature do not address the whole of reality.  The closest thing we have in physics to a comprehensive “theory of everything” is the Standard Model.  As far as I understand it, if we could subsume gravity into the Standard Model, we would have a theory that explains all the fundamental forces in nature.  But the Standard Model will never be used to predict the weather, or even the orbit of a planet.   Different, more specific, models are used for those problems.  All models in physics have a “local” nature.  They treat a specific system under a set of well-defined assumptions.

Considered in its entirety then, what does physics mean?  A recent article outlines four possibilities:

• The universe is utterly pointless.  Physical laws mock our efforts to create meaning for our existence.
• There is a “Platonic” reality beyond the one we occupy.
• Physics is about the material world, but there is a God and reality beyond that realm.  Physics and religion are “intellectual cousins.”
• The universe is somehow becoming aware of its own existence, through our observation of it.
• A fifth possibility: we cannot know whether physics really means anything.

Please don’t ask me which one of these positions I endorse.  In one way or another, each one makes sense to me.

I find physics wonderful and fascinating.  I have no doubt it has influenced the way I think about religion, because I tend to be analytical about everything.  But physics doesn’t make me more or less faithful.  I also don’t find anything in physics that argues for or against God’s existence.  The idea that an orderly universe implies an orderly God doesn’t resonate with me.  Why can’t an orderly universe imply no God?  I also find the idea that modern knowledge renders belief in God irrational to be itself irrational.  What known fact or physical law entails God’s nonexistence?

It’s more difficult to express my thoughts about religion.  There is much I do not understand.  There are many beliefs held by Christians, especially conservative evangelicals, that strike me as ridiculous.

My faith is not something I can explain in any sense that I might use the word “explain” in connection with physics.  I simply find that I believe.  Faith grips me, from some source outside myself.

Sometimes I find it easier to state what my faith is not.

My faith is not my agreement with any particular doctrinal statement.   There aren’t very many doctrinal statements that I agree with anyway.  The Nicene Creed summarizes what I’m willing to commit to, but it is not the object of my faith.  And I suspect I interpret several statements in the Creed differently from my friends in other Christian traditions.

My faith is not me trying really, really hard to believe what the Bible says.  I couldn’t care less if the Bible turns out to be wrong on some point.  My faith is not in the Bible.  I am unimpressed by the assertion that a single error in the Bible renders the entire text worthless, a ridiculous standard applied to no other book.  Besides, whether the Bible has any truth to it has nothing to do with my “trying” to believe it.  And I refuse to ignore my external reality when it contradicts the Bible.

My faith is not my emotional response to a beautiful song or a compelling sermon.  While I don’t often show my emotions, I am emotional, and I can be moved as much as the next guy.  But these moments are not nearly the same thing as faith.

My faith is not an assertion that my way is The Only Way.  I am willing to endorse John 14:6, but if you are a conservative evangelical, I can probably guarantee that I interpret that verse differently from you.

My faith is not the result of a “fork in the road” moment where I chose Jesus over hell.  Growing up, I heard my share of fundamentalist alter calls and preaching, and none of it made any lasting impression on me.  I cannot identify a precise moment when I began to believe.  I simply believed.

So what can I say about my faith?

The best I can do is this: My faith is a response to God. Christianity gives me the best framework to understand what I’m going through.

My response is “Yes!”

My understanding comes from the meaning that faith gives to my life.  I do not always understand my own story, but I think understand where it’s going.

The Inclined Plane on Wikipedia

For those who live under a giant rock: Wikipedia is a user-created web-based encyclopedia. In conversation, I usually refer to it as a compendium of “common knowledge,” realizing of course that many elements of common knowledge are not common, and that many elements are flat wrong. Case in point: the Wikipedia entry on the inclined plane. (I refer to the article as it appeared on Sunday afternoon, 28 October 2007. The section on which I comment is reproduced in its entirety below, including the figure and text.)

The inclined plane is treated in detail in virtually every first-year physics course on the planet. I suspect that nearly everyone who took physics in college remembers it. We use it to teach students the quantitative aspects of Newton’s second law in two-dimensions, and to introduce friction. The Wikipedia article, although somewhat brief, touches on both of these. If I were grading the entry as an answer to a exam question, it would earn 3 out of 5 points, meaning that it gets some things correct, but that it also reveals major errors of fact or reasoning unacceptable for a first-year physics student.

Coulomb’s Law and the Direction of the Force

Coulomb’s law presents a unique challenge to physics students struggling to understand how magnitude and direction can coexist in the same quantity–a vector. The difficulty with Coulomb’s law is that electric charge, a property of certain subatomic particles, comes in two types, arbitrarily called positive and negative. For example, the electron carries a negative electric charge, and the proton a positive electric charge. (They have the same magnitude, or amount, of charge.) Because charge can be positive or negative, Coulomb’s law often produces answers that are easily misinterpreted with regard to the direction of the force.

Fun With Orbits, Or How to Slow Down by Speeding Up

Orbits are cool. Let’s see how, shall we?

When a satellite orbits the Earth in a perfect circle, it experiences a centripetal acceleration that depends on its orbital speed v (a constant) and its orbital radius r (also constant):

A centripetal acceleration changes only your direction of motion.  A tangential acceleration changes your speed.  In your car, your steering wheel produces a centripetal acceleration, and your gas and brake pedals produce a tangential acceleration.

The centripetal acceleration experienced by an orbiting satellite is due to the Earth’s gravitational field:

where G is the universal gravitational constant and M is the mass of the Earth. (If you’re going to build a universe, you must decide how strong the force of gravity will be. You do this by setting the value of G. In our universe, and perhaps others, G has the value 6.673 x 10^-11 in SI units.)

Intelligent Observers

An interesting concept in special relativity is the intelligent observer. An “intelligent” observer is one who takes account of the finite speed of light to reason from calculations as opposed to what she sees. A simple example illustrates the concept.