Book excerpt: Why having Daredevil form images from heat is a very bad idea

Jan 21, 2022

Book excerpt: Why having Daredevil form images from heat is a very bad idea

Jan 21, 2022

Hello all! Well, it turns out I once again failed to deliver on my posting schedule. In my defense, I have been making very solid progress on the book for several months now, and I didn’t want to risk my flow by spending a lot of time doing other Daredevil things. However, I realized that one particular section from my book makes for a pretty good explanation of why remote heat-sensing is a terrible idea. You may recall that I addressed some aspects of this in my previous post on the “world on fire,” though I failed to fully explain why it’s important to have a special organ if you’re going to do what pit vipers do and catch your dinner by heat. This section, which starts out talking about the eye addresses what I failed to mention last time.

The reason I’m posting this now, is that we finally did get some answers about the “world on fire” from season one showrunner Steven DeKnight, that pretty much confirmed some of the suspicions I had. It’s possible that he has talked about this in the past as well, but the post that caught my attention was his December 6 response to a fan about the philosophy behind it, which read: “We wanted to create something different and more visually dynamic than simple echo location. Something that used all of Matt’s senses, not just his hearing.”

So yes, all of his senses indeed, which I can only assume includes heat, since heat-sensing was used explicitly several times throughout the first season. My take on this, of course, is that hearing is the only one of Matt’s remaining senses (if you’re not going to use actual “radar”) that can realistically reveal anything solid about the location and spatial dimensions of remote objects. This is one reason that the radar as a “combination of his heightened senses” has never made any sense to me. I also wish that a desire to create something “visually dynamic” had never been a factor in the show. While I can see the appeal to filmmakers, who are naturally resistent to have anything on screen look drab and unexciting, I have to question whether it makes sense to portray the inner world of a blind character as “visually dynamic.” One would think it should be the opposite of that.

I’m not posting the link to the tweet, and I don’t want people tagging DeKnight here. He seems like a wonderful guy who put together an amazing season of television for us, and what is done is done. I just hope that future Daredevil appearances (yea for progress on that front!) will be able to move away from the stuff that just doesn’t make any sense. Hey Marvel, I’ll work for free! 😉

Either way, below is section from the middle of the third chapter of my book. If it seems out of context, well, I suppose it it since you haven’t read the beginning of the chapter. I hope it makes sense in isolation too though. If you have any questions, or if anything is unclear, let me know!


“While we are on the topic of the eye, let us stop for a moment and consider how important the structure of the sensory organ itself can be to its overall function. If we took this amazing retina we have just showered with praise, and removed it from the back of the eye, all connections intact, and carefully placed it on the cheek instead, what do you think would happen? Would you be able to see an image of anything? The answer is a resounding no.

Primitive ‘eyes’ called eyespots work a little something like our cheek-retina (although the retina of a modern human is, of course, vastly more complex). The problem with having a flat patch of photoreceptors just sitting on the skin like that is that a beam of light activates all of them at the same time, regardless of where the light is coming from. This of course extends to every light-source, whether direct or reflected. It’s like opening an image in Photoshop and applying ‘average blur.’ What you end up with is no image at all, but a solid color that is an average of all the hues in the picture.

The next step between this and a fully functioning vertebrate eye is to make an indentation for the retina to sit in, so that the photoreceptors are at least shaded from light falling from some angles. We are still dealing with a complete blur, but one that may at least be a little brighter where most of the light is falling. This makes it possible to detect the direction of light, and moving light, but what we are seeing is not an image, by any stretch of the imagination.

If we continue by making the indentation deeper, and start closing it up in front, the eye in our thought experiment will start to resemble something called a pinhole eye. The nautilus, a species of mollusk, is an example of an animal with eyes like these that function similarly to a pinhole camera. The pinhole constrains the amount of light that falls on the retina, and also naturally ‘directs’ light from different areas of the scene in front of it to fall on different areas of the retina. We can now legitimately start talking about the eye forming some kind of image, but it is still very blurry compared to what we and most other vertebrates see.

What we have, and the nautilus doesn’t, is a lens that sits behind the pupil, and a rounded cornea that makes up the front of the eye over the iris and pupil. Both of these structures, the lens in particular, take the pinhole eye and turn it into an optical superstar by precisely directing the incoming light. The role of a well-behaved lense in casting a sharp image upon the retina should be clear to everyone who wears glasses. It is by combining the image-forming capacity of the eye with the fine makeup of the retina, that we are able to extract the maximum amount of information from the light stimulus itself.

Since Daredevil is a blind superhero, we probably don’t expect his creators to get the very act of seeing wrong. And yet, this sometimes happens in surprising ways. One fundamental misunderstanding of the science that bears mentioning in the context of eyes and optics appeared in several places in the first season of the Daredevil television show. I am talking about the notion that Matt can sense sources of heat remotely, and do so in ways that suggest that these impressions can make a kind of image.

First of all, the human skin works nothing like the film of a camera, and does not have any special ability to detect photons the way the retina does. This is true whether we are talking about visible light, or the longer wavelength infrared radiation which emanates from all objects in proportion to their temperature. The latter can be made visible to us by special cameras or goggles that translate these wavelengths into something we can see, but the emphasis here is on ‘see.’ As you may remember from what we have covered already on the topic of thermosensation, photosensitivity to infrared light is not the process by which the skin detects heat.

However, even if we were to go along with the idea that Matt’s skin functions like a large retina that can detect infrared radiation, he would not be able to form an image this way. Instead, his skin would be like one giant thermosensitive eyespot. He might be able to tell the relative location of a particularly warm (or, in this context ‘bright’) object, but his skin could not form an image anymore than a retina on your cheek can. In fact, the few animals in nature that can use thermosensation to detect the precise location of prey, which include a family of snakes called pit vipers, are only able to do so by combining traditional thermosensation with specialized organs. What do these so-called pit organs look like? As it turns out, they form a cavity with a smaller opening – not unlike a pinhole camera – to make a crude image!

To suggest that Matt can detect that a woman passing by has skin that is ‘too hot,’ as in the scene of him as a boy with his mentor Stick, is no less of a stretch than to suggest that he can literally see with his skin. I doubt that the show’s writers had any real sense that this is what they were doing, but it underscores how difficult it can be for creators of any era to fully divorce themselves from the logic of vision.”


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