Alexander Klein (14:12)
Yeah. Let me preface this by acknowledging your reaction to the experiments, which I think is pretty widespread. These are gruesome experiments. I say in the book somewhere that they do shock the conscience and they're not things that I am in any way advocating that we revive and repeat. There are some moral problems with these experiments, in my view, and I'll describe them in a moment. But let me say also that, you know, in the first draft of this book manuscript, I had a referee, I had said somewhere, oh, these experiments are really not done anymore. They wouldn't pass muster in terms of, like research boards and all of this. And I had a referee sort of push back on that and say, are you sure? And, you know, started sending me examples of essentially vivisection experiments that are still being done. And I had to look a little deeper into this. And I realized that I would like to say that this sort of work is not done anymore. That is not true. These kinds of experiments are absolutely still done today. The difference is that as a research program, vivisection just doesn't dominate physiology in the way that it did in the 19th century. In the 19th century, there's a sort of sense that, like anybody who's anybody by the late 19th century is doing vivisection experiments in one way or another. That is not the case anymore, I think, thankfully. But I do want to just acknowledge that, yes, we have different standards. We sort of say you need to have a real benefit in view to justify doing vivisection experiments, I.e. experiments on live animals where you're removing or disconnecting various nervous structures. So, you know, maybe the standards are a bit higher, but. But it is. It is still done. Anyway, they're difficult experiments to talk about because they're a bit gruesome. But let me try to give you a quick sense of how they work and why some of them caused a lot of philosophical controversy. So the big one I talk about in the book was an experiment done on headless frogs originally by a physiologist named Edward Pfluger. So this is done in the early 1850s. I guess what you need to know about this is that it may be surprising, but frogs, and it turns out that many vertebrates can survive without A brain. Frogs and cold blooded creatures can even survive without a brain stem. The brain stem controls autonomic functions like heartbeat and respiration. But frogs can survive even without those brain structures in place. So that had long been known by the middle of the 19th century. But Pflueger did this kind of unusual experiment on living headless frog. And it goes like this. He starts by dripping a bit of acid on the side of the frog and then observing which foot the frog uses to wipe off the acid. Now, so far so good. Like people had known for a long time that living headless creatures still have a ton of reflexes preserved, right? So a defensive reflex where like the foot kind of snaps into action and wipes away the acid. And that by itself was not very surprising when Pflueger did his experiment. But Pflueger had caused a huge philosophical controversy because of sort of the second step in the experiment. What he does is he impedes that original foot that has been used to do the wiping. In the first step. Sometimes he amputates the leg, sometimes he, you know, sews it up in some way. But he basically prevents the frog from using that foot to wipe. He then repeats the procedure. He drips the acid in the same place. And apparently what you observe is that the frog will typically dry for a little bit to wipe away the acid with that original foot. But it won't just kind of helplessly wave away, wave around its stump, right? Like if this was like a blind reflex, that's what you would expect, right? You put the acid in the same place. If it's a reflex, you should just get the same response. But that's not what happens right after the frog, you know, is like waving away, waving around its stump a bit. It, it tries different means to wipe away the acid. And so typically what it will do is it will reach around in an awkward way with the other foot and use that other foot to wipe away the acid. And there's a number of means, ends, choosing kinds of examples like this, that these headless frauds were shown to be capable of. So, okay, why is that philosophically interesting? Well, it looks like you have an example of purposive action, right? It's like goal directed behavior. You've got a case where the creature seems to have a goal in view, in mind, however you want to put it. And it's trying different means to achieve that goal. Now for a fully intact frog, this perhaps not surprising that, you know, a frog is capable of goal directed behavior. But for a frog that has no brain that is a very surprising result, right? Means ends choosing has often been appealed to as a marker that a creature is conscious, right? A very common view in the history of psychology has been that means ends choosing is made possible by the conscious mind, right? We are able to try different means to achieve an end. Because we are conscious. We can hold a goal, as I said before, in view, right? We can hold it in mind. So here we've got a creature that has no brain at all. It has no brain stem. I mean, it has really no brain structures in place at all. And it is capable of means ends choosing. That is very surprising. Luger and yet a number of allies concluded that probably there's some measure of consciousness in a brainless frog. This sort of view went along with what grew into emergentism and philosophy of mind. Because people on Pfluger's side developed a kind of holistic story about consciousness, right? Where, okay, maybe consciousness arises from a whole nervous system, you know, if it's sort of complexly enough structured. But this reading of the experiment was challenged almost immediately. You have, um, a number of people on the other side who think, okay, this is preposterous. If the frog is no brain, it no brain structures at all. There's no way it's conscious. And what this should really tell us is that actually purposive behavior is not a very good marker for consciousness. But so what you got was this kind of stalemate, right? You could sort of accept means ends choosing as a marker for consciousness. And then you read the experiment as supporting some kind of holism about the emergence of consciousness from the nervous system. Or you could go in the other direction, right? And say, okay, what this shows us is that means ends choosing is not a good marker of consciously guided action. And the people on that other side tended to support much more mechanistic views of physiology. Eventually, this kind of experiment was used to support epiphenomenalism. So TH Huxley is the classic example of this. He looked at the Pflueger experiment and he said, look, just as you look at the headless frog and you see that it's capable of performing purposive actions even without a brain. Even without consciousness, he would say. Huxley said, well, we have to reason the same way. Even about healthy, intact human beings, right? Maybe even when we walk and talk and do very sophisticated purposive things in our lives. Maybe the lesson we should learn from the frogs is that that kind of sophisticated purpose of action that human beings are capable of is probably possible in a purely mechanical way. You know, it can be caused by a fully intact brain and conscious experience needs play, needs to play no role in the production of this kind of activity at all. So one experiment, two very different interpretations of the experiment. You go one way and you get something like emergentism. You go the other way and you get epiphenomenalism and a sort of severely mechanistic view of physiology. Well, it was a kind of interesting conundrum.