A Design Argument From Cognitive Reliability
You are out hiking and the trail becomes faint and hard to follow. You peer into the distance and see what appear to be three stacked rocks. Looking a bit farther, you see another such stack. Now you are confident which way the trail goes.
Your confidence is based on your taking the rock piles as more than merely natural formations. You take them as providing information about the trail's direction, which is to say that you to take them as trail markers, as meaning something, as about something distinct from themselves, as exhibiting intentionality, to use a philosopher's term of art. The intentionality, of course, is derivative rather than intrinsic. It is not part of your presupposition that the rock piles of themselves mean anything. Obviously they don't. But it is part of the presupposition that the rock piles are physical embodiments of the intrinsic intentionality of a trail-blazer or trail-maintainer. Thus the presupposition is that an intelligent being designed the objects in question with a definite purpose, namely, to indicate the trail's direction.
Of course, the two rock piles might have come into existence via purely natural causes: a rainstorm might have dislodged some rocks with gravity plus other purely material factors accounting for their placement. Highly unlikely, but possible. This possibility shows that the appearance of design does not entail design.
Nevertheless, your taking of the rock piles as trail markers presupposes (entails) that they are designed. It would clearly be irrational to take the rock piles as evidence of the trail's direction while at the same time maintaining that their formation was purely accidental. And if you found out that they had come into being by chance due to an earthquake, you would cease interpreting them as providing information about the trail. One must either take the rock piles as meaningful and thus designed or as undesigned and hence meaningless. One cannot take them as both undesigned and meaningful. For their meaning -- 'the trail goes that-a-way' -- derives from a designer.
Now consider our incredibly complex sense organs. We rely on them to provide information about the physical world. I rely on eyesight, for example, both to know that there is a trail and to discern some of its properties. I rely on hearing to inform me of the presence of a rattlesnake. I rely on my brain to draw inferences from what I see and hear, inferences that purport to be true of states of affairs external to my body. The visual apparatus (eye, optic nerves, visual cortex and all the rest) exhibits apparent design. It is as if the eyes were designed for the purpose of seeing. But the appearance of design is no proof of real design. And indeed, human beings with their sensory apparatus are supposed to have evolved by a process of natural selection operating upon random mutations. If so, eye and brain are cosmic accidents.
But if this is the case, how can we rely on our senses to inform us about the physical world? If eye and brain are cosmic accidents, then we can no more rely on them to inform us about the physical world than we can rely on an accidental collocation of rocks to inform us about the direction of a trail.
As a matter of fact, we do rely on our senses. Our reliance may be mistaken in particular cases as when a bent stick appears as a snake. But in general our reliance on our senses for information about the world is justified. Our senses are thus reliable: they tend to produce true beliefs more often than not when functioning properly in their appropriate environments. We rely on our senses in mundane matters but also when we do science, and in particular when we do evolutionary biology. The problem is: How is our reliance on our sense organs justified if they are the accidental and undesigned products of natural selection operating upon random mutations?
To put it in terms of rationality: How could it be rational to rely on our sense organs (and our cognitive apparatus generally) if evolutionary biology in its naturalistic (Dawkins, Dennett, et al.) guise provides a complete account of this cognitive apparatus? How could it be rational to affirm both that our cognitive faculties are reliable, AND that they are accidental products of blind evolutuionary processes? I agree with Richard Taylor who writes:
. . . it would be irrational for one to say both that his sensory and cognitive faculties had a natural, nonpurposeful origin and also that they reveal some truth with respect to something other than themselves, something that is not merely inferred from them. (Metaphysics, 3rd ed. p. 104)
This suggests the following design argument:
1. It is rational to rely on our cognitive faculties to provide access to truths external to them.
2. It is rational to rely on our cognitive faculties only if they embody the purposes of an intelligent designer.
Therefore
3. Our cognitive faculties embody the purposes of an intelligent designer.
To resist this argument, the naturalist must deny (2). But to deny (2) is to accept the rationality of believing both that our cognitive faculties arose by accident and that they produce reliable beliefs. It is to accept the rationality of something that, on the face of it, is irrational.
You are out hiking and the trail becomes faint and hard to follow. You peer into the distance and see what appear to be three stacked rocks. Looking a bit farther, you see another such stack. Now you are confident which way the trail goes.
Your confidence is based on your taking the rock piles as more than merely natural formations. You take them as providing information about the trail's direction, which is to say that you to take them as trail markers, as meaning something, as about something distinct from themselves, as exhibiting intentionality, to use a philosopher's term of art. The intentionality, of course, is derivative rather than intrinsic. It is not part of your presupposition that the rock piles of themselves mean anything. Obviously they don't. But it is part of the presupposition that the rock piles are physical embodiments of the intrinsic intentionality of a trail-blazer or trail-maintainer. Thus the presupposition is that an intelligent being designed the objects in question with a definite purpose, namely, to indicate the trail's direction.
Of course, the two rock piles might have come into existence via purely natural causes: a rainstorm might have dislodged some rocks with gravity plus other purely material factors accounting for their placement. Highly unlikely, but possible. This possibility shows that the appearance of design does not entail design.
Nevertheless, your taking of the rock piles as trail markers presupposes (entails) that they are designed. It would clearly be irrational to take the rock piles as evidence of the trail's direction while at the same time maintaining that their formation was purely accidental. And if you found out that they had come into being by chance due to an earthquake, you would cease interpreting them as providing information about the trail. One must either take the rock piles as meaningful and thus designed or as undesigned and hence meaningless. One cannot take them as both undesigned and meaningful. For their meaning -- 'the trail goes that-a-way' -- derives from a designer.
Now consider our incredibly complex sense organs. We rely on them to provide information about the physical world. I rely on eyesight, for example, both to know that there is a trail and to discern some of its properties. I rely on hearing to inform me of the presence of a rattlesnake. I rely on my brain to draw inferences from what I see and hear, inferences that purport to be true of states of affairs external to my body. The visual apparatus (eye, optic nerves, visual cortex and all the rest) exhibits apparent design. It is as if the eyes were designed for the purpose of seeing. But the appearance of design is no proof of real design. And indeed, human beings with their sensory apparatus are supposed to have evolved by a process of natural selection operating upon random mutations. If so, eye and brain are cosmic accidents.
But if this is the case, how can we rely on our senses to inform us about the physical world? If eye and brain are cosmic accidents, then we can no more rely on them to inform us about the physical world than we can rely on an accidental collocation of rocks to inform us about the direction of a trail.
As a matter of fact, we do rely on our senses. Our reliance may be mistaken in particular cases as when a bent stick appears as a snake. But in general our reliance on our senses for information about the world is justified. Our senses are thus reliable: they tend to produce true beliefs more often than not when functioning properly in their appropriate environments. We rely on our senses in mundane matters but also when we do science, and in particular when we do evolutionary biology. The problem is: How is our reliance on our sense organs justified if they are the accidental and undesigned products of natural selection operating upon random mutations?
To put it in terms of rationality: How could it be rational to rely on our sense organs (and our cognitive apparatus generally) if evolutionary biology in its naturalistic (Dawkins, Dennett, et al.) guise provides a complete account of this cognitive apparatus? How could it be rational to affirm both that our cognitive faculties are reliable, AND that they are accidental products of blind evolutuionary processes? I agree with Richard Taylor who writes:
. . . it would be irrational for one to say both that his sensory and cognitive faculties had a natural, nonpurposeful origin and also that they reveal some truth with respect to something other than themselves, something that is not merely inferred from them. (Metaphysics, 3rd ed. p. 104)
This suggests the following design argument:
1. It is rational to rely on our cognitive faculties to provide access to truths external to them.
2. It is rational to rely on our cognitive faculties only if they embody the purposes of an intelligent designer.
Therefore
3. Our cognitive faculties embody the purposes of an intelligent designer.
To resist this argument, the naturalist must deny (2). But to deny (2) is to accept the rationality of believing both that our cognitive faculties arose by accident and that they produce reliable beliefs. It is to accept the rationality of something that, on the face of it, is irrational.
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