How Does Biological Evolution Deal With This?

Yes, so? Both entomologists and non-science educated people see an insect with remarkable leaf like camouflage. The difference is the entomologist (and the scientifically knowledgeable) know and understand the natural processes which produced that result. A non-science educated person may think a mind did it.

Remember Dawkins’ famous adage:

“Biology is the study of complicated things that give the appearance of having been designed for a purpose.”

The key word there is appearance.


OK, so if we wanted to create a convincing image of a leaf in one go, then intentional design is the only way to do it. However, the evolutionary process can created images just as convincing. It just takes many “generations” to do. See the example below:

Grow Your Own Picture


Which is what I just did.

“Image: 4. A thing or (now esp.) person in which the aspect, form, or character of another is reproduced; an exact likeness; a counterpart, copy.” A camouflaged insect is a reproduction of what a leaf looks like. Hence it is an image but not an intentional one.

What does it mean to “appear to look like”? Looking like is by definition an appearance. In any case, the first looks like JFK by chance but is not an image of him, while the second is an image. My reflection in a puddle is also an image of me. Some images are made intentionally, some aren’t.

I quite agree that both layperson and scientist agree that it looks like a torn leaf. Which has nothing whatever to do with whether it was formed intentionally or not, which is what I commented on. Do you think this shadow looks like a torn leaf?

Do you think that shadow is an intentional image of a leaf, or does it merely appear to be in a leaf shape?


Barnsley’s Fern is a good example of a simple updating function/algorithm that generates complex self symmetric patterns. Change the formula coefficients just a little and you get a different pattern. My point being, each leaf of a real fern doesn’t evolve independently, this is governed by a few key genes controlling expression that allow for incredible variability.

I meant to post the formula itself, but ran out of time. More info here: Barnsley fern - Wikipedia

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It is very important to me. If I look at an image of a leaf, then I’m going to interpret it as intentionally so. That’s why I posed the question. I want to know how you look at it from an evolutionary perspective.

Thanks Steve. I appreciate what you are saying… it’s just that this is the very reason why I posed the question to begin with. There was a way in which I naturally interpreted the image (that it was intended to look like a leaf), and I wanted to know how you and others would, also (presumably, that it was not intended to look like a leaf, but ended up that way by processes of evolution.)

This is exactly what I was getting at and hoping to understand. (@Faizal_Ali was misattributed above but asked the same question.) So, in fact, Dawkins understands what I was trying to say. There is a difference between the image of a leaf, and the appearance of a leaf image.

I understand and have no issue with this. Please don’t misunderstand. I’m not trying to run an “end around” and trick someone. I just want to know how this kind of image is perceived by the evolutionary community.

This is exactly what “appear to look like” means. One is by chance, the other by purpose.

How? What in the world were you doing that was more important? :rofl:

One perspective may to assign the intention to the predator. If it looks like a yummy dinner, the intention is to eat. If it looks like just another leaf, no interest.


Is this ateatempestacup?

So this is all a silly semantic argument? I wish I had that much free time on my hands. :slightly_smiling_face:

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Uh, sorry, what?

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Not to this speaker of English.

I posted a question below my leaf shadow: Do you think that shadow is an intentional image of a leaf, or does it merely appear to be in a leaf shape? Which is it?

It’s not silly and it is not an argument.

Possibly… it was just a question before it became something else.

Right… a shadow is a leaf shape, it is not a leaf image, nor is it a leaf. But this question does not address what I was asking. Evolution is not a being, consequently, it cannot have intent. So, if a pattern evolved on the back of an insect that “looks similar to a torn leaf”, it must not have been intentionally done… If you say that it was (or that it is literally the image of a leaf) you are fueling the ID theories. Rather, it must have changed over time so as to evolve to such a point where it ends up appearing like a leaf… but it cannot be an image of a leaf, because “evolution” doesn’t “know” what a leaf looks like.

You do!!! And I’m on vacation, so I do too.

Sorry but trying to claim a difference between “looks like an image of a leaf” and “appears to look like an image of a leaf” is an exceptionally silly semantic point.

Not according to my Honey-do list. :slightly_frowning_face:


I think he is trying to understand and to communicate. This really is not an argument. Don’t make it one.

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Mike why don’t you give us your definition of “image” because it seems to be a lot narrower than the one the rest of us use. You seem to think “image” must mean “intentionally created to resemble” which in not in any definition I know of.


It addresses what I was asking, which is what you mean by ‘image’. Apparently to you, my reflection in a puddle is not my image, and when someone says that Joe is the spitting image of his father, they mean Joe was intentionally crafted. Just be aware that you’re using your own idiosyncratic definition of the word and that your usage is going to confuse a lot of people.

Right. And the puddle doesn’t “know” what I look like, so my reflection can’t be an image.


A couple of things. I think that you are all thinking that I’m trying to make some creationist / ID point and I’m not. It’s exactly the opposite. My friend Dan Eastwood gave the perfect example, and I skipped right over it. Thanks, @Dan_Eastwood. I always agree with Dan on every point except for fishing and religion.

See Dan’s image below. It is a representation of an equation or algorithm. It looks like a fern, but it is not. If one manipulates the algorithm, then one can change the properties of the image generated. So, if Dan wants to create an image of a blue fern, he may know which parameters must be changed. If he does so, he has created an image of a blue fern because it was intentional. On the other hand, think of this algorithm as an insect. Over time, evolution modifies the properties of the insect such that it results in a pattern that, to a human, appears to be a blue fern.

The point I’m making (and the reason for me asking this question) is that from a creationist / ID perspective, if one intentionally creates an image (a torn leaf, for instance), this can be claimed as evidence for design (in an ID sense.) If a pattern is created independently, by modifying an algorithm or the genetics of an insect, which just happens to result in a particular image, this is NOT evidence for design (in an ID sense.) Over time, the insects are selected based upon the way that the image appears, and this image changes over time so that it appears more and more like a torn leaf. Never, though, is the image intentionally that of a torn leaf, even though it may appear to be a torn leaf.

Dan’s fern looks like a fern, but it is not. It is a pattern that is very similar to a fern.


How then, I wondered, when the back of this insect looks so much like a torn leaf, would evolutionary biologists describe the image without encouraging the ID camp? Most answered how I imagined, but then many of you seemed to think I was taking liberty with what you were saying, and I was not. I do not know your world, but I do know people. I see arguments here and I wonder why they occur. Sometimes they occur because some of the things that you say are taken out of context.

This is why this question was important to me. If you look at @scd 's images above and his comments, you will see that he is imputing intention into the appearance. That’s my take anyhow.

I created the title to this thread because if you answered that it was literally an image of a torn leaf on the back of the insect, people who lean toward the design movement will see that as possessing intention. Evolution, being a result instead of a being, cannot intentionally create an image of a torn leaf on the back of an insect. It can, however, create an image that, over time, results in a pattern that looks enough like a torn leaf that it can provide a degree of protection that gets passed along.

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Not at all. But I do think there’s some danger of you missing how some of us actually think. My problem was with your framing the alternatives as ‘intentional image’ and ‘merely appearance’ (or even ‘merely random’), which seems like the kind of framing that comes from an intelligent design perspective. I took issue with your equation of ‘image’ with ‘intention’ not to be difficult, but because for me ‘image’ says something about mechanism – it implies that there is a causal process that links the original and the image; intentionality is orthogonal to that. The appearance of a leaf in the insect isn’t random – it’s a genuine representation of real leaves. It may be helpful to think of natural selection as a process that transfers information from the environment to an organism’s DNA. Just as a lens can create an image of a scene with or without anyone intending it, natural selection can create an image of leaves in an insect’s form with or without any intent.


That, then, is beyond my knowledge and understanding. I’ve not ever read anything like that nor have I heard mention of it. You’ll have to flesh that out further for me or provide some further information (or links) that explains this process.

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