Saturday, March 08, 2014

Answering Jason Lisle on the Reliability of the Senses

On page two of the comments section of his blog entry Are You Epistemologically Self-Conscious? Christian apologist Jason Lisle has challenged non-Christian visitors to his blog to explain how they know that the senses are reliable. This is a theme which appears in the main entry itself, where Lisle wrote:
Some people might suppose that our sensory organs are reliable because they have survival value. But this does not follow logically. Chlorophyll has survival value in plants; but this does not imply that chlorophyll reliably informs the plant about the outside world.
In response to this, commenter Zilch asked (September 18, 2013):
I don’t know anyone, naturalist or theist, who supposes that our sensory organs have survival value because they provide us with energy from sunlight- do you?
Replying to Zilch, Jason Lisle embedded the following insertion:
You seem to have misunderstood. The question is: "How do we know that our senses are basically reliable[?]"
Apologists for Christianity raise this question in their exchanges with non-Christians quite frequently, and I have previously addressed the matter on my blog: see my entry On the Validity of the Senses in which I answer Dan Marvin’s attempts to make apologetic use of this matter. In that blog, I address the predictable example of a stick dunked in a glass of water appearing to be bent as an attack on the senses, which is actually a testament to their reliability. Doubting the validity of the senses goes back to ancient skeptics such as Pyrrho, who advocated that since we cannot know anything, we should retreat into “noncommittal silence, with respect to all things” (W.L. Reese, Dictionary of Philosophy and Religion, sv. ‘Pyrrho’, p. 622).

In the hands of Christian apologists, the act of raising doubts about the validity of the senses is an attempt to cut thinkers off from any epistemological methodology of looking outward as their means of acquiring data which can be used to inform one’s knowledge of reality. Essentially, the concern is here is to undermine one’s confidence in sense perception as such, thus compelling a thinker to adopt a mystical approach of looking inward, to consult one’s emotions, imaginations and wishes which apologists seek to manipulate through the use of degrading characterizations of rationality, shame and guilt, and intellectual bewilderment.

Of course, since this question repeatedly pops up in Lisle’s and other apologists’ attempts to stifle non-Christian thinkers, it may be inferred that Christian apologists simply do not know how to answer it themselves and consequently project this inability of theirs onto their critics. The whole upshot of Lisle’s line of inquiry here seems geared ultimately to elicit a desired reaction from the non-Christian, one which essentially takes the form of “Duh, I donno! Must be God did it!” From here the apologist, sensing that his opponent has been defeated, will predictably push his god-belief as the solution to the exposed point of ignorance.

Many secular philosophers throughout the ages have done little or no better than the apologists’ own appeal to ignorance. The history of western philosophy has no shortage of thinkers who have adopted some degree of skepticism about the senses and other aspects of man’s nature and epistemology. Some have come right out and condemned the senses as dysfunctional devices of deception while others have taken a more tentative approach, supposing that the senses are typically reliable but susceptible to error or distortion. Christian apologists have assimilated many of the arguments and strains of skepticism, not because they have anything of value to offer to philosophy, but because they have found that skepticism, given its anti-rational nature, provides expedient application for apologetic ends. Their concern is not to answer skeptics per se, but to utilize their stolen concepts in persuading non-believers to abandon any and all confidence they may have in their minds so that religious “presuppositions” can take its place.

There’s a simple, straightforward answer to Lisle’s question, namely that the validity of sense perception is axiomatic. The fundamental recognition of the reliability of the senses, then, is essentially the application of the axiom of consciousness to perception as such. Rational philosophy observes that there are three distinct levels of consciousness: the sensory level, the perceptual level, and the conceptual level. The axiom of consciousness – i.e., the formal, explicit recognition of the validity of consciousness as such – entails the recognition of the validity of all three levels of consciousness. Thus one does not “prove” that consciousness (including the perceptual level) is valid since proof as such presupposes the validity of the three levels of consciousness. To ask for a proof of anything is to grant the validity of consciousness already. Consequently, to suggest in any way that the senses are invalid, prone to error, deceptive, distortive, etc., is to commit the fallacy of the stolen concept. This is because such suggestions make use of the very faculty it is seeking to disqualify.

Thus if Lisle insists that one cannot know with certainty that his senses are reliable, he is in effect denying the axiom of consciousness while making use of his own consciousness. Thus he should not object to a simple challenge, namely:
When Lisle suggests that the senses may not be entirely reliable, he is making use of his own consciousness; he is performing a variety of conscious actions, such as choosing, thinking, inferring, directing his thoughts, etc. Thus Lisle implicitly assumes the validity or reliability of his own consciousness. But how does he validate his own consciousness without assuming its validity? If he says that his god validates his consciousness, he is making use of his consciousness in making such a claim, thus assuming the validity of what’s in question. If he says that his god's merely existing is a precondition to the senses' reliability, he is assuming the validity of his own consciousness and thereby again begging the question. If he says that one cannot know this, he is still using his consciousness to come to this assessment and is thus, yet again, implicitly assuming the validity of what he is called to validate. So on what basis does he assume the validity of his own consciousness?
The proper response to this is not to blank out as his own line of questioning against non-Christians seeks to bring about, but to recognize the axiomatic nature of consciousness and therefore the validity of its three levels. This means, among other things, that there is no cognitive action which we need to take in order to “validate” consciousness. Such action, whether it be an inference, a proof, a discourse, etc., would assume the validity of consciousness from the outset. Thus we are entirely right to affirm the validity of consciousness as an axiom.

Further examination of the nature of the senses as such, in response to Lisle’s line of inquiry, bears this out. To do this, we need to be willing to identify relevant facts which pertain to Lisle’s question about how we know that the senses are reliable. A fundamental fact about sense perception is that it is a biological function. The sense organs are part of the body of the biological organism which possesses them, and their activity is biological in nature. Thus sense perception, as a biological function, is similar to other biological functions in that they are performed by certain organs and organic systems which the organism possesses.

Consider for example digestion. The Wikipedia article on digestion describes the human digestive process as follows (I have removed the many hyperlinks included in the original text):
In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication, a form of mechanical digestion, and the wetting contact of saliva. Saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food. After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. It will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. As these two chemicals may damage the stomach wall, mucus is secreted by the stomach, providing a slimy layer that acts as a shield against the damaging effects of the chemicals. At the same time protein digestion is occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digestive enzymes. 
After some time (typically 1–2 hours in humans, 4–6 hours in dogs, 3–4 hours in house cats), the resulting thick liquid is called chyme. When the pyloric sphincter valve opens, chyme enters the duodenum where it mixes with digestive enzymes from the pancreas, and then passes through the small intestine, in which digestion continues. When the chyme is fully digested, it is absorbed into the blood. 95% of absorption of nutrients occurs in the small intestine. Water and minerals are reabsorbed back into the blood in the colon (large intestine) where the pH is slightly acidic about 5.6 ~ 6.9. Some vitamins, such as biotin and vitamin K (K2MK7) produced by bacteria in the colon are also absorbed into the blood in the colon. Waste material is eliminated from the rectum during efecation.
Clearly there’s no doubt that what is described here is a function of biological organisms (I’m supposing that the digestive process is highly similar in many animals other than human beings). So let us pose Lisle’s own question to this process:
How do we know that digestion is reliable?
To answer this, let us ask: what is the task that we expect a reliable digestive process to accomplish? Clearly it is to make the nutrients in food available for the body to absorb into an organism’s blood stream for life-preserving purposes. Thus we know that digestion is reliable because it successfully processes foodstuffs such that they can be metabolized by our bodies and converted into an energy source. In other words, we know that digestion is reliable because it successfully performs the task of digesting food. If we supposed that the task of digestion was to compose piano sonatas, then clearly we could conclude that digestion is quite unreliable. But that is not digestion’s task. In fact, the fact that we survive from day to day confirms the successful operation of our digestive systems.

Moreover, our digestive systems do what they do automatically, given their nature; they act according to what they are. They are not something we have to guide volitionally: once I have swallowed a slice of an apple that I’ve chewed up, the stomach takes over and does the rest on its own; I do not need to manage the process by some act of oversight. Digestion is not a consciously-regulated process, and its purpose – namely to convert an energy source into a form that the organism’s metabolic system can utilize for its own preservation – is not something that has been consciously installed into the organism’s biology.

From this let me propose a broader principle:
We can know that a biological function is reliable when its activity successfully performs the task that we expect it to perform.
Now let us turn to Lisle’s question:
How do we know that the senses are reliable?
The method used in answering this question when addressed to digestion was first to ask what the task of digestion is. We can only know that a process is reliable if it performs the task we expect it to achieve. So what is the task of the senses? The answer to this is beautiful in its simplicity:
The task of the senses is to give us awareness of objects – i.e., awareness of the things we perceive when we look outward at the world around us.
So the question becomes: Do the senses perform this task successfully? If they do, then we can be certain that the senses are reliable. If they do not, then we would have to conclude that they are not reliable.

For anyone who may be reading this, there’s no mystery here: the answer is a resounding yes: our senses do successfully give us awareness of objects. This would have to be the case for anyone reading this, for what he is reading would be an object and he would not be able to read it if he did not have awareness of it. Thus an attempt to dispute what I have written here would seem only to confirm the truth of what I have written. But more to the point, it should be noted that if a person is perceiving anything, he is perceiving an object, which can only mean that his senses are performing their task successfully. It is also important to note that, like digestion, the activity of the senses is involuntrary. If my neighbor turns his stereo system up to 11 when I’m trying to take a nap, I cannot choose not to hear it; if I stub my toe on bedroom furniture, I cannot choose to feel pleasure instead of pain.

For the purposes of addressing Lisle’s concern, it does not matter what specifically one is perceiving, or what he might identify the objects of his awareness to be. The specific nature of the object one perceives has no relevant bearing on whether or not one’s senses have successfully given him awareness of it; it could be large or small, blue or orange, round or rectangular, furry or stony, wet or dry, wide or narrow, tall or short, etc. Nor does his identification of what he perceives have any bearing on whether or not his senses have successfully given him awareness of an object. Identification of an object one perceives is distinct from merely perceiving it (this distinction is often what is missed by skeptics pressing the kind of challenge Lisle has raises against his non-believing interlocutors). If he sees an object – say a dog – but identifies at something it is not – say he identifies the dog he perceives as a cat – this does not alter the fact that he perceived something, which can only mean that his senses have successfully given him awareness of some object.

So there are two approaches we can take to answer Lisle’s question. The first approach is philosophical in nature, highlighting the axiomatic nature of the concept of consciousness, thus formally acknowledging the validity and reliability of all three levels of consciousness: the sensory, the perceptual, and the conceptual. Denial of this results in the fallacy of the stolen concept.

The second approach is more scientific, examining the nature of the senses given the task which we expect them to perform, namely awareness of objects. Since the senses do in fact successfully give us awareness of objects, they are reliable, just as digesting a meal indicates the reliability of one’s digestive system. Skeptics often ignore these points since they fail to recognize the distinction between perception and identification. Like digestion, perception is not volitional activity. Both are biological functions, and both need to be understood in this context if any conclusions of value are to be drawn about their validity, reliability or functionality.

by Dawson Bethrick

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Blogger johzek said...

The fact that everyone who looks at a pencil partly submerged in water sees the pencil as bent also confirms the validity of our senses. It is not as if some see it as bent and a significant minority see it as straight, or that even some see it as bent sometimes and as straight at other times. The same would apply to any of the common objects of our experience. Everyone agrees that a chair is a chair and not a refrigerator because the disparate visual inputs from these two objects are entirely different. If human beings sometimes perceived a chair and other times perceived a refrigerator from the same sensory inputs the problem would not be with our senses but with the perceptual level of our consciousness. But reality is not like that. We perceive the objects of reality and even so called optical illusions in a consistent manner which only underscores their validity.

March 09, 2014 10:29 AM  
Blogger wakawakwaka said...

well its obvious how Jason Lisle is going to "refute" your arguement Dawson... "god revealed it to me duh"

March 09, 2014 11:32 AM  
Blogger Robert Bumbalough said...

Hello Dawson. Good blog. You did not mention anything about commensurate characteristics' use in ascertaining conceptual common denominators. If as Lisle claims by way of stolen concept he is unable to know his senses are valid, then he is unable to differentiate commensurate characteristics to cognitively apprehend conceptual common denominators necessary for identifying classes of units that can be used to inform concepts. Being able to do that confers a huge survival advantage on an organism. It seems to me his claim that it's logically non-sequitur that the senses are valid in virtue of their survival advantage is false.

Best Wishes.

March 09, 2014 2:23 PM  
Blogger Bahnsen Burner said...

Hi Robert,

Thanks for your comment.

You wrote: “You did not mention anything about commensurate characteristics' use in ascertaining conceptual common denominators.”

You’re right, I did not do this. I don’t think it’s relevant to the points I was trying to make. For my purposes, I deemed that it’s sufficient to underscore the fundamental distinction between simply perceiving an object on the one hand, and identifying it on the other. The two are not the same. Since my focus is on the senses rather than on the process by which we go about identifying what we perceive, I don’t think it’s necessary in the scope of the present inquiry to explore all the nuances of the identification process itself.

You wrote: “If as Lisle claims by way of stolen concept he is unable to know his senses are valid, then he is unable to differentiate commensurate characteristics to cognitively apprehend conceptual common denominators necessary for identifying classes of units that can be used to inform concepts.”

Should Lisle press his view that the senses are not always reliable, I think Peikoff’s words in OPAR (p. 39) will be sufficient at that point:

<< If the senses are not valid, neither are any concepts, including the ones used in the attack. >>

Also, I would press him to address the challenge that I put forward to him above. At least that would provide some light entertainment!

You wrote: “Being able to do that confers a huge survival advantage on an organism. It seems to me his claim that it's logically non-sequitur that the senses are valid in virtue of their survival advantage is false.”

Obviously an organism’s ability to have awareness of the objects in his immediate environment puts him at a great advantage over organisms which do not, especially if it has to move. Plants don’t move from place to place, so they don’t need to be aware of their surroundings in the way that insects, reptiles, fish, birds and mammals do. Similarly for conceptual ability on top of that.


March 09, 2014 8:04 PM  
Blogger Bahnsen Burner said...

But I caution thinkers from appealing to natural selection in order to validate the senses. In his book The Biological Basis of Teleological Concepts, Harry Binswanger includes a section subtitled “Attempts to base epistemology on evolution.” In it, he has this to say (p. 191):

<< A related epistemological issue is whether or not one can appeal to evolution, not in regard to the theory of action, but in regard to epistemology itself. It has not infrequently been argued that the general validity of man’s consciousness (on the sensory and/or conceptual levels) is assured by the fact that mans’ brain has been exposed to natural selection, and consequently that any types of brain not affording contact with reality have been eliminated. This argument is ultimately circular since the acceptance of the principle of natural selection already presupposes the general validity of one’s mind. The principle of natural selection is a very derivative item of knowledge which rests on and requires the validity of a vast body of observations and on the validity of logical inference. Hence the attempt to justify observation and inference on the basis of natural selection begs the question on a grand scale. >>

He goes on to say (p. 192) that this line of argument mischaracterizes natural selection since “selection does not guarantee that every member of an adapted species will inherit the same adaptive genes.”

Binswanger concludes the section with the following point (p. 192):

<< All of this goes to show not that man’s mind is invalid – its validity is an axiom presupposed in any inquiry, thought, or discussion – but that any attempt to settle basic epistemological issues by appealing to conclusions from the special sciences grossly violates the necessary hierarchical order of knowledge. >>

So I think it’s best to go with the axioms and focus precisely on what we mean by “the senses” – i.e., the sensory and perceptual levels of consciousness. Since rationality is the commitment to reason as one’s only source of knowledge, his only standard of judgment, and his only guide to action, and since reason is the faculty which identifies and integrates the material provided by the senses, there is no rational justification for denying the validity of the senses. Deny the validity of the senses and along with it goes all objectivity. What’s left if not blatant recourse to emotions, imagination and wishing (none of which would be available to us anyway without outside input via the senses)?

Clearly Lisle is not approaching any of this in an “epistemologically self-conscious” manner.


March 09, 2014 8:04 PM  
Blogger Bahnsen Burner said...

Hi Johzek,

Welcome to my blog. I think this is the first time I’ve seen you comment here. I’m glad you stopped by.

You wrote: “The same would apply to any of the common objects of our experience. Everyone agrees that a chair is a chair and not a refrigerator because the disparate visual inputs from these two objects are entirely different.”

Yes, I think you’re right here (and in the rest of your comment). My only concern is what may be taken as an implied appeal to mass agreement. I’m sure you’d agree that the validity of the senses would not hinge on agreement among thinkers (and no, I realize you’re not saying this – I would just be concerned that this is what evaders would take you for saying). A man stranded all alone on a desert island has reliable senses as well. He better, or he won't survive very long.

Even more broadly, though, I think it’s important to maintain focus strictly on the task that the senses by their nature perform – namely giving us awareness of reality, of objects, of things that exist, regardless of what they may be. If I see something, even if I don’t know what it is I’m seeing, my sense organs (eyes I this case) are successfully performing their task. Thus their reliability is beyond dispute. Case closed.

Now, if I opened my eyes and I saw nothing, I would seek an explanation: is there no light? Well, without any light whatsoever, my eyes are not going to give me awareness of objects shrouded in darkness. This would not indicate that the senses are unreliable; reliable does not mean operable without contextual preconditions for their operation. Or, it could be that I’ve lost my eyesight for some reason. For example, the optical nerve has been severed, preventing sensory stimulation from reaching my brain. This, too, would not show that the senses are unreliable. It would simply underscore the need for my sense organs to be connected to my brain for them to give me awareness of things.

This underscores at the very least the dependence of consciousness on physical conditions, if not serving as evidence that consciousness is physical in some way. Apologists will say that we cannot see or touch consciousness. But can we see or touch digestion? Who would argue that digestion is not physical? What’s missed here is the fact that, like digestion, consciousness is a type of activity. It is a type of action. Apologists implicitly treat consciousness as if it were an “entity” of sorts – some independently existing thing, a “spirit”, that is separate from the body but only temporarily housed in it. Their religion requires them to treat it this way. It has no factual basis whatsoever. It’s a fantasy.

Hope that helps!


March 09, 2014 8:24 PM  
Blogger Luiz Claudio said...

Jesus was very clear about this subject:

Luke 4:18
And Jesus said "The Spirit of the Lord is on me, because he has anointed me to proclaim good news to the poor. He has sent me to proclaim that we need sense perception to form concepts, and consequently, self denying propositions like "sense perception is unreliable" He who has ears to hear, let him hear"

March 09, 2014 10:49 PM  
Blogger Bahnsen Burner said...

Ha, good work, Claudio! I see you're quoting from the Revised Amalgamated Version (REV) of the Scriptures. Nice! I'm still waiting for mine to be delivered. I understand it settles a lot of matters that have cropped up over the past 2000 years since Jesus did his ministerial work here on earth.

The following passage from the REV, which was provided to me by insider sources, helps to clarify something that has puzzled me since my days as a baby saint. This is where Paul strickens the magician Elymas for trying to thrwart his evangelism efforts. Acts 13:11 reads:

<< And now, behold, the hand of the Lord is upon thee, and thou shalt be blind, not seeing the sun for a season. And immediately there fell on him a mist and a darkness; and then God immediately afflicted him with acute conjunctivitis, and he went about seeking some to lead him by the hand. >>

And to think, such knowledge was there all this time, buried beneath the surface of the text, and just waiting for some inspired team of translators to come along and reveal it to us all! Praise the Lard!


March 09, 2014 11:14 PM  
Blogger Robert Bumbalough said...

Hello Dawson. Excellent points from Binswanger earn kudos. Many Thanks for helping to clear that up. :)

March 10, 2014 7:03 AM  

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