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Showing posts with label brain. Show all posts
Showing posts with label brain. Show all posts

Thursday, July 14, 2016

The Irrational Faith of the Naturalist



Does man have an immaterial soul or is nature and the material world all there is? Atheists deny the existence of the supernatural, but they also tend to believe there is no fundamental immaterial substance to human beings, either. All our thoughts, feelings, and existence could be reduced to physical states like chemical reactions or electrical impulses. We call this belief philosophical naturalism as the person who holds it believes the natural world is all there is.

One of the greatest problems the naturalist faces is how to account for the fact that human beings are conscious creatures. We can think abstractly and conceive ideas. While many have attempted to explain the evolutionary biological development of man, no one seems able to offer any explanation of the evolution of consciousness, as Richard Swinburne has noted. They just assume that consciousness will pop into existence if the body is complex enough. But how is that science?

J.P. Moreland, in his book The Recalcitrant Imago Dei underscores the problem:
Prior to the emergence of consciousness, the universe contained nothing but aggregates of particles/waves standing in fields of forces relative to each other. The story of the development of the cosmos is told in terms of the rearrangement of micro-parts into increasingly more complex structures according to natural law. On a naturalist depiction of matter, it is brute mechanical, physical stuff. The emergence of consciousness seems to be a case of getting something from nothing. In general, physio-chemical reactions do not generate consciousness not even one little bit, but they do in the brain, yet brains seem similar to other parts of organisms' bodies (e.g., both are collections of cells totally describable in physical terms). How can like causes produce radically different effects? The appearance of mind is utterly unpredictable and inexplicable. This radical discontinuity seems like heterogeneous rupture in the natural world. Similarly, physical states have spatial extension and location but mental states seem to lack spatial features. Space and consciousness sit oddly together. How did spatially arranged matter conspire to produce non-spatial mental states? From a naturalist point of view, this seems utterly inexplicable.1
Thomas Nagel has also complained that naturalists are shirking their responsibility in assuming the appearance of consciousness. Although Nagel is an atheist, he also recognized consciousness is something fundamentally different than physical reactions which can be explained in materialist terms. In other words, your mind is not your brain. He concluded any account of consciousness on natural grounds alone would fail, writing "since a purely materialist explanation cannot do this, the materialist version of evolutionary theory cannot be the whole truth."2

Evolutionists and naturalists have left a gaping hole in their theories. The retort of "we'll find it; we just haven't yet" is akin to a man telling the IRS "I know I owe you money, but I'm going to win the lottery soon and when I do, I can pay you." It's another of those science-of-the-gaps claims. But the naturalist isn't even playing the right lottery as he keeps taking his chance betting on material items when the lottery is being played with immaterial numbers.

There's no avoiding the problem of consciousness for the naturalist. Any science that continues to assume one can get something from nothing isn't explaining anything; it's simply a statement of faith. And it's the most irrational kind of faith at that. Christians don't even believe that we can get a something from a nothing. We at least start with God.

References

1. Moreland, J.P. The Recalcitrant Imago Dei: Human Persons and the Failure of Naturalism. (London: SCM Press, 2009). 24.
2. Nagel, Thomas. Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False. New York: Oxford UP, 2012. 45. Print

Tuesday, March 18, 2014

Why Evolution Cannot Produce a Mind

Yesterday, I posted an article declaring how the mind is a fundamentally different kind of thing than the brain. I wanted to follow up with a couple of possible objections to the mind/brain distinction that people offer today. The first objection is known as emergence and its proponents claim that the mind, while different from the brain, emerges as the brain grows in complexity. Thus the mind is distinct from the brain but it is the evolution of the brain, growing more and more complex, that eventually produced the first mind.

Emergent properties are familiar in both science and philosophy and they basically mean that the whole cannot be described solely by describing its parts. For example, we can talk about a snowflake by its chemical composition. A snowflake is comprised of nothing more than H2O in a solid state. However, describing the chemical bonds that create H2O does not describe a snowflake. The snowflake is something more specific than the chemical reactions of H2O, and thus a snowflake is an emergent property of H2O. Flocks of birds, molds, even societies are used as examples of emergence, where these things are different than the sum of the parts. 1

Materialists will then use this kind of description to say that the mind may be an emergent property of the brain. It exists because the brain's chemistry and electrical pathways are arranged in a specifically complex fashion. Just as the molecules of water or the grouping of people to form a city emerges as a new property that didn't exist in that entity's building blocks, so the mind emerges as a new property of the brain's makeup. Thus, they claim, the mind is a real property but it comes from the physical structure and function of the brain. No soul is required.

The Problems with Emergence

The explanation sounds good, but there are several problems with the claim that the mind is emergent. First, in a complex system where new properties emerge, those new properties fall into the same domain as the system's constituent parts. In other words, any physical emergent system will produce emergent properties that can be described physically. Water may have properties that hydrogen and oxygen lack such as the ability to crystallize into a snowflake. However, a snowflake is still describable by using the chemical language of solid/liquid/gaseous states and crystalline structures. The components are physical and the new property is also physical. Likewise, cities emerge from groups of people getting together and choosing to live a certain way. People are sociological and cities are described sociologically.

The mind however produces mental properties. As we've said, mental properties are non-physical. Therefore there is still a difference in kind in the property one is trying to account for. How does one account for non-physical properties from purely physical substances?

Secondly, emergence runs into the problem of impotence. J.P. Moreland notes that if the complexity of the brain produces a mind "like fire produces smoke or the structure of hydrogen and oxygen I water 'produce' wetness," then the mind is nothing more than an effect of the brain and it therefore has no causal powers. J.P. writes that if this was the case, "mental states are byproducts of the brain, but they are causally impotent. Mental states merely 'ride' on top of the events in the brain." 2

If this is true, then we cannot change our minds, really. We can only dance to the electro-chemical reactions that are happening in our heads. In other words, we have no free will whatsoever! We are simply victims to whatever processes our body and any outside events that we come in contact with cause. We are not making decisions, but our brains, like so many dominoes falling in a row, are just following the rules of chemistry and physics. The mind is simply the smoke, but it's the fire of neurons in the brain that's doing all the work.

The self-refuting nature of a material view of self

Because a purely material origin for the mind leads to determinism, such a description can be seen as contradictory. J.P. quotes from H.P. Owen who says:
Determinism is self-stultifying. If my mental processes are totally determined, I am totally determined either to accept or reject determinism. But if the sole reason for my believing or not believing X is that I am causally determined to believe it I have no ground for holding that my judgment is true or false.3
I think Owen and Moreland are right here. Much like the argument from reason, trying to relegate our conscious awareness to the physical becomes a fool's errand of determinism and contradiction. Such suggestions really don't explain why unique properties of the mind exist and it leads us to conclude that no one really makes any free choices. That's an awful lot to give away in order to escape the necessity of the soul.

References

1 For examples of emergence as used popularly today, see this slideshow provided by the PBS science show Nova.
2. Moreland, J.P. and William Lane Craig. Philosophical Foundations for a Christian Worldview. Downer's Grove, Il.: InterVarsity Press, 2003.240.

3. Ibid. 241.

Thursday, March 13, 2014

Has Science Found Consciousness in the Brain?

Yesterday, I talked about how brain imaging techniques could not read your thoughts. I said that it is not really possible to know which areas of the brain are responsible for discreet thoughts. Some may say, "Sure, we can't know exactly what thoughts people think, but we can certainly identify consciousness." It turns out that the brain doesn't have a true sign of consciousness. It has normal patterns that we see in most people, but as Dr Alva Nöe states, simply because there is a deviation from that pattern does not mean that the person is not conscious. He writes (The emphasis is mine):
Here what confronts us is not so much direct evidence of the lack of consciousness as the absence of normal brain-imaging findings. Does the absence of normal brain profiles in patients in the persistent vegetative state help us decide whether they are sentient or not? Would the mere absence of normal patterns of neural activity as modeled by functional imaging technologies such as fMRI or PET satisfy you that your loved one was now little more than a vegetable?

Actually, things are more complicated. Although patients in the persistent vegetative state show markedly reduced global brain metabolism, so do people in slow-wave sleep and patients under general anesthesia. But sleepers and surgery patients wake up and resume normal consciousness, whereas patients in the persistent vegetative state rarely do. Remarkably, in the small number of cases in which brain imaging has been attempted in patients who have recovered from the persistent vege­tative state, regaining full consciousness, it would appear that global metabolic levels remain low even after full recovery. Moreover, external stimuli such as sounds or pinpricks produced. Significant increases in neuronal activity in primary perceptual cortices. Interesting new work by Steven Laureys and his col­leagues in Belgium indicates that vegetative patients show strik­ingly impaired functional connections between distant cortical areas and between cortical and subcortical structures. In addi­tion, they show that in cases where consciousness is recovered, even if overall metabolic activity stays low, these functional con­nections between brain regions are restored. These findings are important and point in the direction of a deeper understanding of what is happening in the brain in the persistent vegetative state.

But this doesn't change the fact that at present we are not even close to being able to use brain imaging to get a look inside the head to find out whether there is consciousness or not. Consider these simple questions: Does a patient in the persistent vegetative state feel physical pain—for example, the pain of thirst or hunger, or the prick of a pin? Does she hear the sound of the door slamming? We know she turns her head in response to the sound, and we know she withdraws her hand from the pin­prick. We also know that there is some Significant neural activity produced in primary perceptual cortices by these stimuli. Is the patient in the persistent vegetative state a robot, responding reflexively to stimulation, but without actually feeling anything? And, more important, is this something that brain imaging could ever help us decide?

We don't know how to answer these questions. It is disturbing to learn that so far there are no theoretically satisfying or practically reliable criteria for deciding when a person with brain injury is conscious or not. At present, doctors and relatives have to deal with these questions without guidance from science or medicine. For example, the press tended to treat the widely discussed case of Terri Schiavo as one in which science, armed with cold hard facts about the nature of Schiavo's brain damage, did battle with family members who were blinded at once by their love for their daughter and their religious fundamentalism. Sadly, science doesn't have the hard facts.1
It's interesting that we don't hear these kinds of nuanced explanations from the press when they cover such stories. We're led to believe that science will always have all the answers and that because the brain-imaging scanners make multi-colored maps we can really see inside the head. I appreciate Dr. Nöe's explanation and I think that it shows how cautious we must be when dealing with issues like consciousness. Tomorrow, I will talk more directly about what consciousness is and why it cannot be based on something physical. But for now, let us take some care before assuming that we've already got everything worked out. Such sentiments are more a sign of hubris than knowledge

References

1. Nöe, Alva  Out of Our Heads: Why You Are Not Your Brain, and Other Lessons of Consciousness.
New York: Hill and Wang, 2009. 19

Wednesday, March 12, 2014

Can Neuroscientists Use MRI Imaging to See Thoughts?

Is it possible to see someone think? Can a machine ever capture the thoughts of another person, their dreams or imaginations? A lot of people think that science is almost to that point, but they really don't realize just how different thoughts are from brain activity.


Some of this confusion stems from the fact that the media are not really good at nuancing their stories when they report on things like brain scanning techniques. One such example is the reports that began to circulate when scientist used an fMRI scanner to measure blood flow through the visual cortex of the brain while people were looking at a specific image. They then built a computer to map the blood flow and they reproduced a kind of silhouette of the image itself. This isn't surprising, really, since blood flow to the visual cortex is a chemical response to stimulus from the optic nerve, kind of the same way film has a chemical reaction to light exposure. However, UC Berkeley's newsroom carried the story with the headline "Scientists use brain imaging to reveal the movies in our mind" and  wrote, "Imagine tapping into the mind of a coma patient, or watching one’s own dream on YouTube. With a cutting-edge blend of brain imaging and computer simulation, scientists at the University of California, Berkeley, are bringing these futuristic scenarios within reach."

This makes for great sharing on the Internet, but fMRI imaging is nothing like understanding what someone dreams or imagines. In fact, it has a really hard time telling scientists what is even going on when they can see activity in the brain. Alva Nöe, another professor at UC Berkeley and a member of the Institute for Cognitive Brain Sciences does a great job describing just how crude tools like fMRI really are. In his book Out of Our Heads: Why You Are Not Your Brain, and Other Lessons of Consciousness, he explains:
"PET and fMRI yield multicolored images. The colors are meant to correspond to levels of neural activity: the pattern of the colors indicates the brain areas where activity is believed to occur; brighter colors indicate higher levels of activity. It is easy to overlook the fact that images of this sort made by fMRI and PET are not actually pictures of the brain in action. The scanner and the scientist perform a task that is less like gathering a photographic or X-ray image than it is like the process whereby a police sketch artist produces a drawing of a suspect based on interviews with a number of different witnesses. Such drawings carry valuable information about the criminal, to be sure, but they are not direct records of the criminal's face; they are, rather, graphical renderings based on perhaps conflicting reports of what different individuals claim to have seen. Such a composite sketch reflects a conjecture or hypothesis about, rather than a recording of, the perpetrator. Indeed, there is nothing in the process that even guarantees that there is a single perpetrator, let alone that the sketch is a good likeness.

"In a similar way, images produced by PET and fMRI are not in any straightforward way traces of the psychological or mental phenomena. Rather, they represent a conjecture or hypothesis about what we think is going on in the brains of subjects. To appreciate this, consider that we face a problem from the very beginning about how to decide what neural activity is relevant to a mental phenomenon we want to understand. Scientists start from the assumption that to every mental task—say, the judgment that two given words rhyme—there corresponds a neural process. But how do we decide which neural activity going on inside you when you make a rhyming judgment is the neural activity associated with the mental act? To do that, we need to have an idea about how things would have been in the brain if you hadn't performed the rhyming judgment; that is, we need a baseline against which to judge whether or not the deviation from the baseline corresponds to the mental act. One way to do this is by comparing the image of the brain at rest with the image of the brain making a rhyming judgment. The rhyming judgment presumably depends on the neural activity by virtue of which these two images differ. But how do we decide what the brain at rest looks like? After all, the brain is never at rest. For example, there are stages of sleep when your brain is working harder than it does at most times during the day!" (Emphasis added)1
So, to see things like thoughts that exist only in your conscious mind and are not produced by external stimulus are nothing like the images that MRIs produce. You may say, "But at least we can see what happens when someone is looking or talking, right?" Nope. You still have to ask the patient what he or she is experiencing. Nöe goes on:
"Comparison provides the best method available for uncovering the areas of the brain that are critically involved in the performance of a cognitive function. For example, suppose you were to produce a bunch of PET images of people listening to recordings of spoken words and then making judgments about whether given pairs of words rhyme. To isolate the activation responsible for the rhyming judgment, as distinct from that responsible for the auditory perception of the spoken words, a standard procedure would be to compare these images with a second set of images of people listening to recordings of spoken words but not making rhyming judgments. Whatever areas are active in the first set of images, but not the second, would be plausible candidates for the place in the brain where the rhyming judgment takes place.

"This method of comparison is cogent and it holds promise. But it is worth stressing that its reliability depends on a number of background assumptions, not all of which are unproblematic, as Guy C. Van Orden and Kenneth R. Paap have convincingly argued. For one thing, sticking to our example, the comparison method assumes that there is no feedback between what the brain is doing when we make a rhyming judgment and what the brain is doing when we perceive the words. If there is indeed feedback, then it would follow that overlapping regions in the images do not necessarily correspond to a common neural factor."2
Because there is so much activity in the brain, it becomes really difficult to construct an objective model of even which areas of the brain are involved in which discreet process. And even that makes an assumption that thoughts can be relegated to a single area of the brain. We don't know that to be true. What we do know is that consciousness is something completely different than brain activity. I'll talk more about that in an upcoming post. Just don't let news reports or popular movies lead you to believe otherwise.

References

1. Nöe, Alva  Out of Our Heads: Why You Are Not Your Brain, and Other Lessons of Consciousness.
New York: Hill and Wang, 2009. 20.
2. Ibid. 21.
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