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Hank: Over the centuries, the effort to craft a perfect, bullet-proof argument for the existence of God has taken many forms. There was the ontological argument of Anselm. There were the four cosmological arguments of Aquinas. And they still have their supporters. But many modern philosophers feel that they’re simply too flawed -- too inconsistent with our scientific understanding of the universe -- to be convincing today. But there was a fifth argument posited by Thomas Aquinas. And it was popularized several hundred years after his time -- in the late 1700s, by the English Christian philosopher William Paley. And this argument for God’s existence is still around today, too. In fact, it’s one of the most popular. It’s known as the teleological argument. You may know it as Intelligent Design.   [Theme Music]   To make his case for the existence of God, William Paley gave us what’s known as an argument by analogy. This form of inductive argument invites us to consider a particular state of affairs -- let’s just call it Situation A -- about which we’re already likely to have certain beliefs, and then likens it to Situation B, with which we are less familiar. The idea is that, in the interest of consistency, whatever conclusions we’ve drawn about A, we ought to draw about B as well.

You can make an argument by analogy about anything, but Paley used it to talk about God, in what’s known as the Watchmaker Analogy. He asked us to imagine what we’d think if we found a watch on the ground. Would we imagine that the watch simply appeared randomly, spontaneously, on its own? Or would we see the complexity of it, and notice that its parts seem to come together in a particular way in order to accomplish a goal? If so, wouldn’t we think that the watch must have been made by someone, on purpose? Paley was arguing that the teleology demonstrated by a watch would lead us to conclude that it was designed by an intelligent creator with a particular end in mind.

Teleological means goal-oriented, or purposeful. And we can easily pick out the teleologies of man-made objects. Got a mug here, as an example -- it was created with a particular teleology in mind. It was designed to hold a liquid without leaking. It’s got a handle put here deliberately, in such a way that human fingers could easily fit into it, and its composition is such that it’ll keep the liquid inside warm without burning the hand that holds it. We wouldn’t assume that a coffee cup would simply come to be, exhibiting such perfect design for its particular function, without someone having created it that way on purpose. So, in the same way that the teleology of a cup implies the existence of a cup maker, and that of a watch implies the existence of a watchmaker, Paley saw teleology in the world, and assumed from that, God’s existence.

He continued his analogy by comparing a watch to a living organism. Look at the complexity of the human body. Heart and lungs working together, producing sweat to keep ourselves from overheating, transforming food into energy – we’re just generally amazing all around.Look at how elements of the natural world operate according to complex laws that sustain a beautiful, natural harmony. Paley said this couldn't possibly just have happened, any more than the design of a pocket watch could just have happened. There must be a designer. If you accept this analogy, then you agree with Paley that, just like the purposefulness of a watch compels us to believe in a watchmaker, the purposefulness of the world compels us to believe in a worldmaker – God.

And you might think this is a fantastic argument. It might even be what motivates your own belief in God. There are lots of people who say things like sunsets and babies show them that there must be a designer-god. But some of you probably aren’t buying it – and you know what to do! Arguments are refuted by counterarguments, so when you want to refute an argument by analogy, you offer a disanalogy. Basically, you demonstrate that Situation A and Situation B are dissimilar enough that the analogy doesn’t actually work. So, to object to Paley, we have to identify a way in which elements of the natural world – like human bodies – are relevantly dissimilar to watches.

When we’re talking about a watch, an objector might say, it obviously had a creator. After all, we can take it apart and see clearly how the gears fit together to move the hands and keep time. But there’s so much in the natural world that isn’t understandable in the same way. For instance, why would God have designed our eyes to have a blind spot? Paley responded that it doesn’t matter whether we can understand how something was created. The point is simply that it was. He might point out, for instance, that I actually don’t understand the inner workings of my phone. But I still know it had a creator. Whether or not I can understand how it was created is beside the point.

Next objection: Some parts of nature seem to be without purpose. A blind spot obviously doesn’t have any function, and neither do nipples on a man. Paley’s response here was: Just because we don't know there's a purpose doesn't mean there isn't one. But this is a problem, too, because his whole argument for believing in God is that you should look at the world and see purpose. So if we see some things in the world that are working great, and really seem to have complexity and a definite use, and others that don’t, that’s a flaw in his argument. What’s more, the absence of any obvious purpose in things can lead people to start searching for purposes, and effectively make them up.

For instance, I could find a purpose for this finger – I could use it as a nose-picker. It would make a good one – it’s just the right size to really get in there and dig around. But was my finger designed to pick noses? Probably not. 20th century British philosopher Bertrand Russell made fun of this purpose-finding tendency, by pointing out that you could look at a bunny and form the belief that God gave it a fuzzy white tail so hunters would have something to shoot at.

The point is: If we're the ones inventing purposes, rather than recognizing ones that are inherently there, then we’re the real creators of purpose in the world, not God. Basically, if you believe that God made eyes for seeing, then you also have to believe that he designed fingers as nose-pickers, and rabbit tails as bullseyes, and blind spots as ways for us to get into car accidents. So the counterargument here is: We don't get to just pick and choose, and say God designed the stuff we want him to have designed, and not the other stuff.

Rather than searching for disanalogies, another way Paley’s argument has been countered is with an alternative explanation for Condition B. Paley says bodies are purposeful, and from there concludes that the purpose had to have been put there by an intelligent creator. But another explanation for how bodies came to have the complexity and functionality they have today, is natural selection and random mutation. We can concede that the existence of a designer-god helped make sense of the origins the our world in a pre-scientific age, but now we have a perfectly good scientific explanation for how the complexity of the world came about. So, who needs a watchmaker when you have evolution by natural selection?

Another objection to Paley’s case came from 18th century Scottish philosopher David Hume, who pointed out that, if we’re to take the analogy seriously, we’d need to conclude that the creator that Paley posits seems to make a lot of mistakes. And not just blind spots. Like, how about hurricanes? Or why would he make bodies with certain tissues -- like in the breast, or prostate, or colon -- that are so incredibly prone to cancer? Why would he make umbilical cords that could wrap around a baby’s neck? Why would he make butterflies have to wait for hours, immobile, for their wings dry as soon as they come out of their chrysalis, making them easy prey for predators?

Hume pointed out that the world is chock full of stuff that looks cruel, ridiculous, impractical, and contrary to life. A flawed world, he said, implies a flawed creator. Now, the development of evolutionary biology over the past couple hundred years has taken a pretty heavy toll on the teleological argument. But it still has many supporters, and their method of defending their view is a good model for the way the Socratic method is supposed to work.

When your opponents raise objections to your theory, you need to either reject it, or modify it in a way that responds to those objections. So, supporters of the teleological argument set out to modify – and strengthen – their view. Here are a couple of modern responses: Contemporary British philosopher Richard Swinburne gives us a modern teleological argument with a twist of probability. He says that, even if there’s another possible explanation for the universe, we should go with the explanation that’s most likely to be true. And he says that it’s simply more probable that God designed the world, than that it came about through the pure chance of evolutionary processes.

Likewise, another class of modern defenses of the teleological argument are collectively known as Fine-Tuning Arguments. These arguments accept the Big Bang and evolution as scientific truths, but they maintain that, for the evolution of life to occur, it’s most likely that God set up the precise conditions that it required, rather than them coming about by accident. After all, if Earth were just a little closer to, or farther from, the sun... If the composition of our atmosphere was slightly different... If the content of our oceans was something other than what it is... Life would have never taken root.

A lot of people think these modernized arguments have more going for them than Paley’s did. This is partly because these types of teleologists have moved from making assertions about certainty to making claims about probability, which seem easier to get right and to defend. Objectors will counter by saying that the problem with these arguments is, you can’t really make a probability claim when you only have a sample set of one. If we had multiple Earths that we could examine, we could see how likely any particular adaptation is, or how unique the conditions for life are. Then we would know if it were likely or unlikely to happen without God. But we can’t know that -- at least not now -- because we can only access this one world, where we know that things evolved as they did.

Thus, the counterargument goes, Swinburne and other modern teleologists are right to recognize that if things were slightly different, then life maybe wouldn’t have evolved or would have evolved very differently. But that is wholly different from claiming that it’s unlikely to have happened in the first place.

So, today you learned about the teleological argument, objections to it, and responses to those objections, and the responses to the responses to the objections. But we’ve spent an awful lot of time talking about God’s existence, so next time, let’s consider what god is like, if it exists.

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Crash Course Philosophy is produced in association with PBS Digital Studios. You can head over to their channel and check out amazing shows like The Art Assignment, The Good Stuff, and Blank on Blank. This episode of Crash Course was filmed in the Doctor Cheryl C. Kinney Crash Course Studio with the help of all of these amazing people and our equally fantastic graphics team is Thought Cafe.