Witches, goblins, and gremlins with magical powers, kings hand-picked by God, glass spheres with star-holes encapsulating the earth, rocks falling to earth because they want to be where they belong...

Yup, the cluelessness of past generation's assumptions is laughable. It makes us proud we've overcome it. It also makes us wonder what we assume today that will look clueless to future generations.

To overcome cluelessness, we try to doubt all of our assumptions. But you can't doubt assumptions you don't know you make.

If I had to bet where we're most clueless today, it would be about causality. We think science has licked it, but some persistent mysteries suggest that we're missing something. I know, I know. Whenever someone says there's more to causality than meets the eye, responsible thinkers say, "Uh-oh, blast from the past, I'm about to be pitched on some magical woo-woo gremlin power."

I'm not pitching gremlins. In fact, the opposite, I'm arguing that while scientists claim victory in purging the gremlins, they're still harboring stow-aways they don't notice or won't acknowledge. They try to explain life by dissecting it into its parts, but then ambiguously treat the parts as both lifeless as rocks and as purposeful as gremlins. For example, we treat genes as nothing more than chemical strands, and at the same time the builders and organizers of bodies. Likewise, we treat brains as meat-webs of trigger cells, but also as the seat of the soul. Exposing this problem, Biologist Paul Weiss, winner of the prestigious National Medal of Science said:  “In trying to restore the loss of information suffered by thus lifting isolated fragments out of context, we have assigned the job of reintegration to a corps of anthropomorphic gremlins. As a result, we are now plagued-or blessed, depending on one's party view-with countless demigods, like those in antiquity, doing the jobs we do not understand: the organizers, operators, inductors, repressors, promoters, regulators, etc.,—all prosthetic devices to make up for the amputations which we have allowed to be perpetrated on the organic wholeness, or to put it more innocuously, the "systems" character, of nature and of our thinking about nature.”
 
I promised constraint propagation for this column. It's a key to what I think future generations will say we were missing about causality. That will be next column. But first, to reveal the blind-spot, a very short history of thought about causality:

We hear the first careful wondering about the nature of causality in Aristotle. He distinguished four kinds, and to illustrate them, describes how all four contribute to a house being built:

Material cause:  The lumber, nails, windows.
Formal cause:  The plans for configuring the materials
Efficient cause:  The carpenter's work, hammering nails; sawing wood.
Final cause: The goal or final end--that for which the house is built--providing future shelter to someone.

For centuries people assumed everything had its four causes, with their final causes built right into them. You are born with your purpose built right into you. A rock falls to the ground because being on the ground is the rock's final cause--its goal.

The church came to see things Aristotle's way too. God was the carpenter (efficient cause) of the universe, he had the plans (formal cause) and the goal or purpose (final cause) for all matter (material cause).  He had endowed everything with its purpose.

Kings and popes claimed that their plans were God's plans and that people should simply get with God's program. By the end of the middle ages though, people started to wonder about it, spurred by frustration with the oppression perpetrated in God's name, the conflict between supposedly God-elected leaders, and exposure to successful cultures with different Gods.

And then Newton demonstrated there was no glass ceiling on either the earth or causality--we weren't encased in God's glass spheres as had been thought since Aristotle. All motion on earth and in the infinite heavens could be explained by efficient cause alone. No purpose--just action and reaction.  When asked what final cause or purpose gravity served, Newton said "I wouldn't feign a hypothesis."

Philosophers started to notice that final cause was actually a pretty sketchy concept. How can needing a future house cause the existence of one today? That's backwards causality. Ultimately, the sciences rejected final cause as a kind of blind faith.

Everywhere that efficient cause was successful and began to dominate in explanations, it tended to crowd out final cause. After all if it's all just things bumping into each other, what do you need with purposes. But people weren't going to drop purpose just like that. So there have been clashes and ultimately a rip in the treatment of causality.

An early and significant move like this was made by the Muslims in the late 11th century. Muslims had allowed for both efficient and final cause for centuries. Their science had far outpaced the West's. Suddenly they doubted that you could have it both ways. Either things moved the way they did because a purposeful God moved them, or because of efficient cause. The Muslims at long last decided to surrender more fully to God's purposes and in the process they ended up surrendering their scientific edge to the West. 

And in the West too, there have been repeated backlashes against efficient cause's dominance.  The "Fideists" who said we'll never be able to explain all behavior with efficient cause alone and therefore that we should trust in God or the Bible. Luther, who demanded faith in God's purposes over reason. The romantics--who thought science was killing spirit, and then today's fundamentalists of every stripe who despite their fierce battles against each other share a commitment to some higher purpose as the ultimate and final cause.

Still, with commitment to efficient cause alone, science took off like gangbusters.  It's as though being able to talk about something's purposes had killed curiosity.  You could explain anything by saying "it's meant to do that." Now that purpose was barred from science, people really had to figure out how to explain what causes things by means alone, not by ends. Why was there lightning?  Not so God could purposefully threaten and punish sinners, but because of the discharge of electro-magnetic energy.  The question "Why?" in science stopped meaning "to what end?" and became instead "by what means?"

And science claimed victory.  No more gremlins.

Except they keep showing up, for example in what's called the functionalist approach to biology where evolution itself is treated as a master gremlin. Evolution is both a passive statistical process whereby things simply last different lengths of time, and it's also the blind watchmaker, the innovator, creator and designer of functional parts.  Where the ambiguity is most exposed is in evolutionary psychology, a source of great insights but also often a weakly disciplined inquiry in which so long as you can come up with a trait's function or purpose, you don't have to wonder much by what means it arose.

Science based exclusively on efficient cause isn't going to cut it.  There is final cause, or else we simply can't explain the radical shift in that appears with life and mind. Next piece will get at constraint propagation as promised.  And if we researchers interested in it are onto something, you'll be among this generation's first to know about and apply it.