Foucault's pendulum at CA Academy of Sciences

Faith and science

One of my (many) favourite exchanges in Carl Sagan’s magnificent novel Contact is that between the book’s protagonist, radio astronomer Dr Ellie Arroway, and charismatic preacher, Palmer Joss, about faith.

“Here, take a look out of that window,” says Ellie. “There’s a big Foucault pendulum out there. The bob must weigh five hundred pounds. My faith says that the amplitude of a free pendulum – how far it’ll swing away from the vertical position – can never increase. It can only decrease.

“I’m willing to go out there, put the bob in front of my nose, let go, have it swing away and then back toward me. If my beliefs are in error, I’ll get a five hundred pound pendulum smack in the face. Come on. You want to test my faith?”

When the time comes to test Ellie’s faith in science, she holds the bob to her nose and lets it swing. The bob swings away, comes to a halt, then reverses trajectory, rapidly gaining in speed, looming in size in front of her.

She gasps. And flinches.

What is the relationship between faith and science? Do scientists even have faith? Should they? It might seem offensive to some to even suggest that they do.

To many people of a scientific, rationalist, skeptical or philosophical bent, faith is a bad word. It has unsavoury connotations associated with dogma, superstition and, primarily, religion. Faith is anathema to reason, to a sceptical eye, to the process of questioning and seeking evidence to support our beliefs.

But do not scientists have faith that the universe is an ordered and explicable place? Faith that the laws of physics operate in a uniform fashion throughout all space? Faith that observation and evidence can give genuine knowledge about the natural world? Rational and scientifically minded folk are often accused of hypocrisy by the more religiously minded for having faith, yet denying that science itself is based on faith.

Perhaps the toughest claim to deny is that the science advocate has faith that the world tomorrow will be much like the world today. However, as David Hume pointed out, we have no reason to believe this to be true. Thus, to the extent that we believe the world tomorrow will exhibit the same regularity as the world today – a claim that underpins the scientific method – we have faith.

And, you know what, I think that’s OK. Faith itself isn’t always a bad thing. It’s just often misunderstood. As is the distinction between what we might call “rational faith” and “blind faith”.

Scientists, rationalists, skeptics and philosophers have faith, of a kind. But it’s not the same kind of faith as that touted by many religious believers. And in distinguishing these types of faith, those of a naturalist bent can stave off claims of hypocrisy from those of a supernaturalist tilt.

Rational faith can be defined as holding a belief that something is true without comprehensive evidence to prove that it is true.

We have this kind of faith in all manner of things. We have faith that the universe is ordered and explicable. We have faith that our partners love us. We have faith that all the hard work we’re doing now will pay off some day etc.

And there is nothing irrational about holding this kind of faith – as long as we also allow our beliefs to change in the face of evidence to the contrary. This is what separates rational faith from blind faith.

Blind faith is believing that something is true regardless of any evidence to the contrary. It is also the rejection that there even could be any evidence to the contrary. It is a belief maintained in the face of alternative explanations that are more probable, parsimonious or expeditious. It is a belief held no matter what. And that is clearly anathema to the rationalist or scientific approach.

Drawing a clear line between rational faith and blind faith might be difficult, but there are many cases that comfortably fall into one camp or the other. The faith that tomorrow will be like today could erode if tomorrow, and the day after, are sufficiently different enough from today. The faith that someone’s rapid recovery from a disease is due to the intervention of an invisible supernatural being is likely to be rather more resistant to erosion in the face of evidence to the contrary.

What about Ellie’s gasp? Does this mean she lacked faith in science? Not necessarily. I see it as indicating she had more immediate faith in her powerful instinctive reactions when it came to imminently looming five hundred pound bobs than in the abstract notions of mass, acceleration and friction.

In fact, it shows that her faith in science really was rational. So much so that she was capable of a kind of doubt in the face of overpowering evidence to the contrary. And yet her ability to recognise and understand this in retrospect – and thereby learn more about her psychology – might even serve to then reinforce her faith in science.

Faith isn’t all bad. The good kind just confronts the world with its eyes wide open rather than blindly.

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