How Does Evolution Explain Design? Part 3: Does Natural Selection Make an Increase in Complexity Inevitable?

Guest Post by Andrew Rogers

In his book, Did Darwin Write the Origin Backwards?, Philosopher of biology Elliott Sober makes an argument for why natural selection will inevitably lead to an increase in complexity.

Sober says that, “Complexity increases from life’s beginning because of the initial conditions, not the laws. This is analogous to the random walk depicted in figure 1.1. A marker on a line changes position because of a coin toss. If the coin lands heads, you move the marker one space to the right; if the coin lands tails, you move the marker one space to the left. These are the rules of change unless the marker happens to be at the left-most or the right-most points. If the coin lands tails when the marker is at the extreme left, you simply toss again. Suppose the game begins with the marker placed at the left-most point on the line. Where will the marker be after five or fifty or five hundred coin tosses? Probably not at square one. Even if selection is indifferent to simplicity versus complexity, evolution by natural selection can still be expected to manifest a net increase in complexity.” (Sober 2011, p. 17).

Is this really analogous to natural selection. There are two assumptions in Sober’s analogy that bother me:

Assumption 1: If an organism goes below the level of complexity required for evolution then it gets to “flip again.”

Assumption 2: The odds of a mutation leading to an increase of complexity are the same as the odds of a mutation leading to a decrease in complexity.

In regards to Assumption 1, it seems that if an organism has to deal with a mutation that pushes it below the level of complexity required for evolution, then that organism would simply die out without any offspring. This is definitely not the same as getting to flip another coin until it gets an increase in complexity.

So that part of the analogy should be changed to “If the coin lands tails when the marker is at the extreme left, you simply toss again die and leave no offspring!” Even with this change it could be argued that with enough life forms and enough offspring there will be an inevitable increase in complexity.

This brings me to Assumption 2. Is the probability of a mutation increasing complexity really the same as the probability of a mutation decreasing complexity? This seems unlikely if the mutations are random. If I randomly start hitting my keyboard without looking is it more likely to decrease or increase the complexity of this paper?

Lk/nhcSDzkumelri

Looks like a decrease in complexity to me and I would bet good money that the vast majority of random keyboard smacks would likewise decrease complexity.

To be clear, my argument is not that there wasn’t an increase of complexity throughout evolutionary history—I’m pretty sure there was. And my argument is not that God must have intervened in order for this increase in complexity to occur—I’m pretty sure it could have happened without God intervening. My argument is that the mechanism of natural selection alone does not entail an inevitable increase in complexity (or even a high probability of an increase in complexity). 

How Does Evolution Explain Design? Part 2: The Tautology Problem

Guest Post by Andrew Rogers
 
1. The Design Argument
You’re playing poker with me (Andy) and three other people. In order to keep it as simple as possible, let’s say it’s five card draw without the draw, so everyone is dealt five cards and then the best hand wins (not a very exciting version of poker to be sure, but the best one for the analogy I want to make). Also, I’m dealing every hand for some reason.

Now the first five hands in a row I get a royal flush. You get suspicious and start to think that I might be cheating—that my hands may have been “designed.”

Of course, it’s possible that I could get five royal flushes in a row without cheating, but it seems extremely unlikely to you. You think it is more likely that my hands were designed.

You are using a design argument to make the case that I am cheating.

2. Young Earth Creationism
Your first theory of how I’m cheating is that I have a royal flush up my sleeve and that I switch the cards I’m dealt with the cards in my sleeve every hand. So before the next hand you check my sleeves.

But there is nothing up my sleeves. Therefore, your theory that I created my royal flush through a “recent fully formed special creation” by pulling the cards out of my sleeve has been falsified.

But does this nullify your original design argument? No, you still have good reason to think that I’m cheating. All that has been done is that you’ve just eliminated one possible way that I may be cheating.

3. Intelligent Design Theory
Your next theory as to how I’m cheating is that I deal everyone else’s cards fairly but that I’m dealing my own cards off the bottom of the deck (dealing off the top and the bottom is indistinguishable to most observers if one deals fast enough). Your theory is that I have the cards needed for a royal flush on the bottom of the deck and cheat by dealing my own hand from the bottom.

So before the next hand you check the bottom of the deck. But there is no royal flush on the bottom.

You thought that I was performing some intervention during the dealing process by dealing my own cards off the bottom, but it turns out that the right cards for a royal flush are not on the bottom.

So your second theory of how I’m cheating has been falsified. But, once again, this doesn’t mean that your theory that Andy is somehow cheating has been falsified.

4. Explaining Away Design With Natural Selection
Now at this point I can tell that you think I’m cheating so I try to dissuade you of your suspicion. I explain to you that there is a new theory that explains why I got five royal flushes in a row, namely, the theory of Poker Evolution.

I explain that the mechanism of the theory is known as Poker Natural Selection. The way this mechanism works is that it selects only the fittest cards for my hand through a purely naturalistic process that requires no intervention from the dealer.

I explain that each time I go around the table dealing one card to each person (in poker, hands are dealt one card at a time) only one out of five cards survives and makes it to my hand. This is captured by the slogan “survival of the fittest card.” This explains why I always get a royal flush—since I always get the card with the highest fitness!

Something about this explanation just doesn’t seem right to you.

So then you ask me “Well what is fitness? What makes it true that a certain card is the fittest?”

I respond: “It’s simple. A card has the highest fitness if it survives the trip around the table.”

But if fitness is nothing more than a term for the card that survives, then we can restate the mechanism of Poker Natural Selection as “survival of the card that survives.” This means that the mechanism tells us nothing more than that I will always get the cards that I will get. It’s true of course, but it’s not a useful explanation and it certainly doesn’t dissuade you of your suspicion that I’m cheating.

5. The Fine-Tuning Argument
At this point you come up with a third theory as to how I’m cheating; you propose that I may have stacked the deck so that every fifth card is one of the cards needed for a royal flush. You propose that I have “fine-tuned” the order of cards in the deck so that I will get a royal flush even without any actual intervention during the dealing process.


6. The Purpose of the Analogy
Humans have always had the suspicion that “someone was cheating”: that the universe wasn’t completely random. There have been many different theories of how exactly this cheating took place; there have been as many different creation stories as there have been different cultures.

There have been theories that God(s) created all life on earth fully formed just as we see it today within the not too distant past. Today people who defend this view are often called “Young Earth Creationists”. There seems to be some good evidence against this view, but that doesn’t mean that there isn’t still good reason to think someone cheated. Analogously, just because there aren’t any cards up my sleeves doesn’t mean that I didn’t cheat in some other way.

There is also a theory that certain things were specially created by God or that certain things required a special intervention by God in the natural world. For example, Michael Behe defends the view that some things in nature are “irreducibly complex” and could not have come about through purely natural processes. This theory is very difficult to falsify since it would require a detailed account of a possible story of evolution for everything on earth. But even if it is falsified or at least shown to be unlikely, that still wouldn’t mean that the original suspicion that someone cheated has been falsified.

There are two points that I wanted to make with the poker analogy. The first point is that the design argument is not refuted simply by refuting a specific theory of divine intervention. The second point is that proposing Natural Selection as a mechanism is irrelevant to the design argument if natural selection is a tautology (a statement that is true by definition such as "all bachelors are unmarried men"). If fitness just is survival, then “survival of the fittest” is not explanatory.

I’m sure many people will object that I am getting natural selection wrong here. I am aware that there are many different views on natural selection and that many of them are not tautologous. In the following posts I will explore whether any of these definitions are explanatory and, if so, what relevance they have to the design argument.

How Does Evolution Explain Design? Part 1: Introduction

 Guest Post by Andrew Rogers

There are two ways in which evolution has traditionally been thought to undermine Christianity.

The first is that it challenges the historical claims made in the Bible about the age of the earth and the order and nature of creation.

For example, if the Bible claims that all land animals and humans were made within the 6th 24-hour day of creation, then evolution would seem to falsify Christianity (if it is assumed that the Bible makes this historical claim and that Christianity is false if at least one of the historical claims of the Bible is false).

The second way in which evolution has been thought to threaten Christianity is that it nullifies the biological design argument for the existence of God. In the words of biologist Richard Dawkins:

“An atheist before Darwin could have said, following Hume: "I have no explanation for complex biological design. All I know is that God isn't a good explanation, so we must wait and hope that somebody comes up with a better one." I can't help feeling that such a position, though logically sound, would have left one feeling pretty unsatisfied, and that although atheism might have been logically tenable before Darwin, Darwin made it possible to be an intellectually fulfilled atheist.” -The Blind Watchmaker (1986)


Dawkins expresses what I think is the mainstream view-- that evolution destroys the biological design argument because it gives an alternative explanation for the appearance of design in biology.

Some Christians respond to this by completely rejecting evolution (Young Earth Creationists such as Ken Ham). Some Christians respond by rejecting some part of evolution (Irreducible Complexity proponents such as Michael Behe). Some Christians respond by focusing on other arguments such as the fine-tuning argument, the moral argument, and the cosmological argument (Theistic Evolution proponents such as Francis Collins, Kenneth Miller, and Josh Willms).

In this series of articles, I will put aside the issues of whether evolutionary history contradicts the Bible and of whether there is good evidence for evolution. Instead I will focus on how exactly it is claimed that evolution explains away the appearance of design in biology.

I will not be concerned with the historical claims of evolutionary theory; instead I will presuppose the historical claims and analyze the claims evolutionary theory makes about forces, causes, laws, and mechanisms and how those claims relate to explaining away the appearance of design.

Farewell For a Time

Dear Readers,

Medical school is really (really) hard, so I need to take a break from blogging for about 9 months. In the meantime, Andy Rogers, a graduate student in philosophy, will be posting material relevant to searching for truth. I hope you enjoy his posts!

Thank you so much for following my blog, I love all of you!!!

And I will be back.

Josh