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How philosophy blends physics with the idea of free will
How does philosophy try to balance having free will with living in a deterministic universe?
- People feel like they have free will but often have trouble understanding how they can have it in a deterministic universe.
- Several models of free will exist which try to incorporate physics into our understanding of our experience.
- Even if physics could rule out free will, there would still be philosophical questions.
Most people with a scientific worldview agree with the idea of causal determinism, the notion that everything is subject to the laws of physics, and anything that happens is the result of these laws acting on how things exist in the world or existed in a prior moment. However, it can be challenging to figure out how this idea meshes with the notion of free will.
After all, if everything else is subject to causal determinism, how can we not be? How can our decisions be somehow exempt? Many people argue that we obviously are also part of a clockwork universe and that physics kills off free will.
But is this saying too much? Can we really treat free will as the subject of physics alone? Today, we'll consider some stances on free will and how they relate to physics alongside some philosophers' ideas on if we can outsource our views on the human experience to science.
Some philosophers have taken the argument of casual determinism mentioned above and used it to say that there is no room for free will at all. This stance, called "hard determinism," maintains that all of our actions are causally necessary and dictated by physics in the same way as a billiard ball's movement.
The Baron d'Holbach, a French philosopher, explained the stance:
"In short, the actions of man are never free; they are always the necessary consequence of his temperament, of the received ideas and of the notions, either true or false, which he has formed to himself of happiness; of his opinions, strengthened by example, by education, and by daily experience."
While physics and philosophy have both advanced since the enlightenment era, hard determinism still has supporters.
As some of you are probably thinking right now, quantum physics, with its uncertainties, probabilities, and general strangeness, might offer a way out of the determinism of classical physics. This idea, sometimes called "indeterminism," occurred to more than a few philosophers too, and variations of it date back to ancient Greece.
This stance holds that not every event has an apparent cause. Some events might be random, for example. Proponents of the perspective suggest that some of our brain functions might have random elements, perhaps caused by the fluctuations seen in quantum mechanics, that cause our choices to not be fully predetermined. Others suggest that only part of our decision-making process is subject to causality, with a portion of it under what amounts to the control of the individual.
There are issues with this stance being used to counter determinism. One of them is that having choices made randomly rather than by strict causation doesn't seem to be the kind of free will people think about. From a physical standpoint, brain activity may involve some quantum mechanics, but not all of it. Many thinkers incorporate indeterminism into parts of their models of free will, but don't fully rely on the idea.
Also called "compatibilism," this view agrees with causal determinism but also holds that this is compatible with some kind of free will. This can take on many forms and sometimes operates by varying how "free" that will actually is.
John Stuart Mill argued that causality did mean that people will act in certain ways based on circumstance, character, and desires, but that we have some control over these things. Therefore, we have some capacity to change what we would do in a future situation, even if we are determined to act in a certain way in response to a particular stimulus.
Daniel Dennett goes in another direction, suggesting a two-stage model of decision-making involving some indeterminism. In the first stage of making a decision, the brain produces a series of considerations, not all of which are necessarily subject to determinism, to take into account. What considerations are created and not immediately rejected is subject to some level of indeterminism and agent control, though it could be unconscious. In the second step, these considerations are used to help make a decision based on a more deterministic reasoning process.
In these stances, your decisions are still affected by prior events like the metaphorical billiard balls moving on a table, but you have some control over how the table is laid out. This means you could, given enough time and understanding, have a fair amount of control over how the balls end up moving.
Critics of stances like this often argue that the free will the agent is left with by these decision-making models is hardly any different from what they'd have under a hard deterministic one.
This is the stance with the premium free will people tend to talk about—the idea that you are in full control of your decisions all the time and that casual determinism doesn't apply to your decision-making process. It is "incompatibilist" in that it maintains that free will is not compatible with a deterministic universe.
People holding this view often take either an "agent-casual" or "event-causal" position. In an agent-casual stance, decision-makers, known as "agents," can make decisions that are not caused by a previous action in the same way that physical events are. They are essentially the "prime movers" of event chains that start with their decisions rather than any external cause.
Event-casual stances maintain that some elements of the decision-making process are physically indeterminate and that at least some of the factors that go into the final choice are shaped by the agent. The most famous living proponent of such a stance is Robert Kane and his "effort of will" model.
In brief, his model supposes an agent can be thought responsible for an action if they helped create the causes that led to it. He argues that people occasionally take "self-forming action" (SFA) that helps shape their character and grant them this responsibility. SFAs happen when the decisions we make would be subject to indeterminism, perhaps a case when two choices are both highly likely- with one being what we want and one being what we think is right, and willpower is needed to cause a choice to be taken.
At that point, unable to quickly choose, we apply willpower to make a decision that influences our overall character. Not only was that decision freely chosen, but any later, potentially more causally-determined actions, we take rely at least somewhat on a character trait that we created through that previous choice. Therefore, we at least partially influenced them.
Critics of this stance include Daniel Dennett, who points out that SFAs could be so rare as to leave some people without any real free will at all.
Can’t we just outsource free will to physics?
No, the question of free will is much larger than if cause and effect exist and apply to our decisions. Even if that one were fully answered, other questions immediately pop up.
Is the agency left to us, if any, after we learn how much of our decision-making is determined by outside factors enough for us to say that we are free? How much moral responsibility do people have under each proposed understanding of free will? Is free will just the ability to choose otherwise, or do we just have to be responsible for the actions we make, even if we are limited to one choice?
Physics can inform the debate over these questions but cannot end it unless it comes up with an equation for what freedom is.
Modern debates outside of philosophy departments tend to ignore the differences in the above stances in a way that tends to reduce everything to determinism. This was highlighted by neuroscientist Bobby Azarian in a recent Twitter thread, where he notes there is often a tendency to conflate hard determinism with naturalism—the idea that natural laws, as opposed to supernatural ones, can explain everything in the universe. .
Lastly, we might wonder if physics is the right department to hand it over to. Daniel Dennett awards evolutionary biology the responsibility for generating consciousness and free will.
He points out that while physics has always been the same for life on Earth, both consciousness and free will seem to have evolved recently and could be an evolutionary advantage of sorts—not being bound to deterministic decision making could be an excellent tool for staying alive. He considers them to be emergent properties we have and considers efforts to reduce us to our parts, which do function deterministically, to be unsound.
How to balance our understanding of causal determinism and our subjective experience of seeming to have free will is a problem philosophers and scientists have been discussing for the better part of two thousand years. It is one they'll likely keep going over for a while. While it isn't time to outsource free will to physics, it is possible to incorporate the findings of modern science into our philosophy.
Of course, we might only do that because we're determined to do so, but that's another problem.
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Certain water beetles can escape from frogs after being consumed.
- A Japanese scientist shows that some beetles can wiggle out of frog's butts after being eaten whole.
- The research suggests the beetle can get out in as little as 7 minutes.
- Most of the beetles swallowed in the experiment survived with no complications after being excreted.
In what is perhaps one of the weirdest experiments ever that comes from the category of "why did anyone need to know this?" scientists have proven that the Regimbartia attenuata beetle can climb out of a frog's butt after being eaten.
The research was carried out by Kobe University ecologist Shinji Sugiura. His team found that the majority of beetles swallowed by black-spotted pond frogs (Pelophylax nigromaculatus) used in their experiment managed to escape about 6 hours after and were perfectly fine.
"Here, I report active escape of the aquatic beetle R. attenuata from the vents of five frog species via the digestive tract," writes Sugiura in a new paper, adding "although adult beetles were easily eaten by frogs, 90 percent of swallowed beetles were excreted within six hours after being eaten and, surprisingly, were still alive."
One bug even got out in as little as 7 minutes.
Sugiura also tried putting wax on the legs of some of the beetles, preventing them from moving. These ones were not able to make it out alive, taking from 38 to 150 hours to be digested.
Naturally, as anyone would upon encountering such a story, you're wondering where's the video. Thankfully, the scientists recorded the proceedings:
The Regimbartia attenuata beetle can be found in the tropics, especially as pests in fish hatcheries. It's not the only kind of creature that can survive being swallowed. A recent study showed that snake eels are able to burrow out of the stomachs of fish using their sharp tails, only to become stuck, die, and be mummified in the gut cavity. Scientists are calling the beetle's ability the first documented "active prey escape." Usually, such travelers through the digestive tract have particular adaptations that make it possible for them to withstand extreme pH and lack of oxygen. The researchers think the beetle's trick is in inducing the frog to open a so-called "vent" controlled by the sphincter muscle.
"Individuals were always excreted head first from the frog vent, suggesting that R. attenuata stimulates the hind gut, urging the frog to defecate," explains Sugiura.
For more information, check out the study published in Current Biology.
Are "humanized" pigs the future of medical research?
The U.S. Food and Drug Administration requires all new medicines to be tested in animals before use in people. Pigs make better medical research subjects than mice, because they are closer to humans in size, physiology and genetic makeup.
In recent years, our team at Iowa State University has found a way to make pigs an even closer stand-in for humans. We have successfully transferred components of the human immune system into pigs that lack a functional immune system. This breakthrough has the potential to accelerate medical research in many areas, including virus and vaccine research, as well as cancer and stem cell therapeutics.
Existing biomedical models
Severe Combined Immunodeficiency, or SCID, is a genetic condition that causes impaired development of the immune system. People can develop SCID, as dramatized in the 1976 movie “The Boy in the Plastic Bubble." Other animals can develop SCID, too, including mice.
Researchers in the 1980s recognized that SCID mice could be implanted with human immune cells for further study. Such mice are called “humanized" mice and have been optimized over the past 30 years to study many questions relevant to human health.
Mice are the most commonly used animal in biomedical research, but results from mice often do not translate well to human responses, thanks to differences in metabolism, size and divergent cell functions compared with people.
Nonhuman primates are also used for medical research and are certainly closer stand-ins for humans. But using them for this purpose raises numerous ethical considerations. With these concerns in mind, the National Institutes of Health retired most of its chimpanzees from biomedical research in 2013.
Alternative animal models are in demand.
Swine are a viable option for medical research because of their similarities to humans. And with their widespread commercial use, pigs are met with fewer ethical dilemmas than primates. Upwards of 100 million hogs are slaughtered each year for food in the U.S.
In 2012, groups at Iowa State University and Kansas State University, including Jack Dekkers, an expert in animal breeding and genetics, and Raymond Rowland, a specialist in animal diseases, serendipitously discovered a naturally occurring genetic mutation in pigs that caused SCID. We wondered if we could develop these pigs to create a new biomedical model.
Our group has worked for nearly a decade developing and optimizing SCID pigs for applications in biomedical research. In 2018, we achieved a twofold milestone when working with animal physiologist Jason Ross and his lab. Together we developed a more immunocompromised pig than the original SCID pig – and successfully humanized it, by transferring cultured human immune stem cells into the livers of developing piglets.
During early fetal development, immune cells develop within the liver, providing an opportunity to introduce human cells. We inject human immune stem cells into fetal pig livers using ultrasound imaging as a guide. As the pig fetus develops, the injected human immune stem cells begin to differentiate – or change into other kinds of cells – and spread through the pig's body. Once SCID piglets are born, we can detect human immune cells in their blood, liver, spleen and thymus gland. This humanization is what makes them so valuable for testing new medical treatments.
We have found that human ovarian tumors survive and grow in SCID pigs, giving us an opportunity to study ovarian cancer in a new way. Similarly, because human skin survives on SCID pigs, scientists may be able to develop new treatments for skin burns. Other research possibilities are numerous.
The ultraclean SCID pig biocontainment facility in Ames, Iowa. Adeline Boettcher, CC BY-SA
Pigs in a bubble
Since our pigs lack essential components of their immune system, they are extremely susceptible to infection and require special housing to help reduce exposure to pathogens.
SCID pigs are raised in bubble biocontainment facilities. Positive pressure rooms, which maintain a higher air pressure than the surrounding environment to keep pathogens out, are coupled with highly filtered air and water. All personnel are required to wear full personal protective equipment. We typically have anywhere from two to 15 SCID pigs and breeding animals at a given time. (Our breeding animals do not have SCID, but they are genetic carriers of the mutation, so their offspring may have SCID.)
As with any animal research, ethical considerations are always front and center. All our protocols are approved by Iowa State University's Institutional Animal Care and Use Committee and are in accordance with The National Institutes of Health's Guide for the Care and Use of Laboratory Animals.
Every day, twice a day, our pigs are checked by expert caretakers who monitor their health status and provide engagement. We have veterinarians on call. If any pigs fall ill, and drug or antibiotic intervention does not improve their condition, the animals are humanely euthanized.
Our goal is to continue optimizing our humanized SCID pigs so they can be more readily available for stem cell therapy testing, as well as research in other areas, including cancer. We hope the development of the SCID pig model will pave the way for advancements in therapeutic testing, with the long-term goal of improving human patient outcomes.
Adeline Boettcher earned her research-based Ph.D. working on the SCID project in 2019.
Satellite imagery can help better predict volcanic eruptions by monitoring changes in surface temperature near volcanoes.
- A recent study used data collected by NASA satellites to conduct a statistical analysis of surface temperatures near volcanoes that erupted from 2002 to 2019.
- The results showed that surface temperatures near volcanoes gradually increased in the months and years prior to eruptions.
- The method was able to detect potential eruptions that were not anticipated by other volcano monitoring methods, such as eruptions in Japan in 2014 and Chile in 2015.
How can modern technology help warn us of impending volcanic eruptions?
One promising answer may lie in satellite imagery. In a recent study published in Nature Geoscience, researchers used infrared data collected by NASA satellites to study the conditions near volcanoes in the months and years before they erupted.
The results revealed a pattern: Prior to eruptions, an unusually large amount of heat had been escaping through soil near volcanoes. This diffusion of subterranean heat — which is a byproduct of "large-scale thermal unrest" — could potentially represent a warning sign of future eruptions.
Conceptual model of large-scale thermal unrestCredit: Girona et al.
For the study, the researchers conducted a statistical analysis of changes in surface temperature near volcanoes, using data collected over 16.5 years by NASA's Terra and Aqua satellites. The results showed that eruptions tended to occur around the time when surface temperatures near the volcanoes peaked.
Eruptions were preceded by "subtle but significant long-term (years), large-scale (tens of square kilometres) increases in their radiant heat flux (up to ~1 °C in median radiant temperature)," the researchers wrote. After eruptions, surface temperatures reliably decreased, though the cool-down period took longer for bigger eruptions.
"Volcanoes can experience thermal unrest for several years before eruption," the researchers wrote. "This thermal unrest is dominated by a large-scale phenomenon operating over extensive areas of volcanic edifices, can be an early indicator of volcanic reactivation, can increase prior to different types of eruption and can be tracked through a statistical analysis of little-processed (that is, radiance or radiant temperature) satellite-based remote sensing data with high temporal resolution."
Temporal variations of target volcanoesCredit: Girona et al.
Although using satellites to monitor thermal unrest wouldn't enable scientists to make hyper-specific eruption predictions (like predicting the exact day), it could significantly improve prediction efforts. Seismologists and volcanologists currently use a range of techniques to forecast eruptions, including monitoring for gas emissions, ground deformation, and changes to nearby water channels, to name a few.
Still, none of these techniques have proven completely reliable, both because of the science and the practical barriers (e.g. funding) standing in the way of large-scale monitoring. In 2014, for example, Japan's Mount Ontake suddenly erupted, killing 63 people. It was the nation's deadliest eruption in nearly a century.
In the study, the researchers found that surface temperatures near Mount Ontake had been increasing in the two years prior to the eruption. To date, no other monitoring method has detected "well-defined" warning signs for the 2014 disaster, the researchers noted.
The researchers hope satellite-based infrared monitoring techniques, combined with existing methods, can improve prediction efforts for volcanic eruptions. Volcanic eruptions have killed about 2,000 people since 2000.
"Our findings can open new horizons to better constrain magma–hydrothermal interaction processes, especially when integrated with other datasets, allowing us to explore the thermal budget of volcanoes and anticipate eruptions that are very difficult to forecast through other geophysical/geochemical methods."