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 (and thus entails) that they are designed. It would clearly be irrational for you to take the 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, say, you would cease interpreting them as meaning anything, as providing information about the trail. One must either take the cairns 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. Their intentionality is derivative, not intrinsic.
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 an unguided or 'blind' 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 twisted tree root 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 materialistic (Richard Dawkins, Daniel 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 evolutionary processes? It cannot be rational. 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, non-purposeful 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., Prentice-Hall 1983, p. 104)
The foregoing may be summed up in 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 materialist 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.
The above is an impressive argument, wouldn't you say? Of course it needs beefing up in various ways. For example, how can we be sure that there is exactly one intelligent designer and not several working in concert? If these worries can be allayed, the argument seems to establish the existence of an intelligent designer of such cognitively gifted animals as ourselves, not to mention the world in which the gifted animals are embedded. Many will be quick to identify this intelligent designer with the God of classical theism. Essential to classical theism as I am using the term is the idea that God is a personal being (tri-personal on normatively Christian accounts) who is transcendent of the physical universe which he creates and sustains in being, and is thus transcendent in the sense that he could just as well exist in his full perfection without having created anything.
But I don't believe the above argument amounts to a proof of classical theism. It does not render the latter rationally inescapable; at best, it renders it rationally acceptable. On classical theism, the intelligibility of nature has a transcendent source: it accrues to nature ab extra, which is to say: it is not immanent in nature. But why couldn't the intelligibility of nature, and with it, the cognitive reliability of the natural faculties with which we investigate nature, be inherent in the natural world? The idea is not that 'Mother Nature' is a person with conscious purposes in the way that God is a person with conscious purposes, but that nature, below the level of conscious mind, is yet mind-like in that it aims at certain outcomes, and thus has 'purposes' in an analogous sense of the term. Dispositionality provides an analogy in the small for the immanent intentionality and teleology of nature in the large.
To say that a wine glass is fragile, for example, is to say that it is disposed to shatter if suitably struck or dropped onto a hard surface from a sufficient height. Several philosophers have noted the analogy with conscious intentionality. A consciously intentional state exhibits
a. directedness to an object;
b. an object that may or may nor exist;
c. an object that may be, and typically is, indeterminate or incomplete.
For example, right now I am gazing out my study window at Superstition Mountain. The gazing is an intentional state: it is of or about something, a definite something. It takes an accusative, and does so necessarily. The accusative or intentional object in question presumably exists. But the intentional object is what it is whether or not it exists. The phenomenological description of object and act remains the same whether or not the object exists. Moreover, the object as presented in the act of gazing is incomplete: there are properties such that the intentional object neither has them nor their complements. Thus, to a quick glance, what is given in the intentional experience is 'a purplish mountain.' Just that. Now anything purple or purplish is colored, and anything colored is extended; but being colored and being extended are not properties of the intentional object as such. No doubt they are properties of the mountain itself in reality; but they are not properties of the precise intentional object of my gazing, which has all and only the properties it is seen to have. Furthermore, in reality, yonder mountain is either such that someone is climbing on it or not; but the intentional object of my momentary gazing is indeterminate with respect to the property of being climbed on by someone.
The same or similar points can be made about dispositions. If a piece of glass is fragile, then it is disposed to shatter if suitably struck. There cannot be a disposition that is not a disposition to do something, to shatter, or explode, or melt.
Second, the reality of a disposition is independent of its manifestation: a fragile piece of glass is actually fragile whether or not it ever breaks. From the fact that x is disposed to F, one cannot infer that x ever Fs. This parallels a feature of intentionality: from the fact that x is thinking about Fs one cannot infer that there exist Fs that x is thinking about. (If I am thinking about unicorns it does not follow that there exist unicorns I am thinking about; if I want a sloop it doesn't follow that there is a sloop I want; if Ernest is hunting lions it doesn't follow that there are any lions he is hunting.)
Third, although a manifested disposition is a fully determinate state of affairs, this complete determinateness is not present in the disposition qua disposition. The disposition to shatter if suitably struck is not the disposition to shatter into ten pieces if suitably struck, although it is of course the disposition to shatter into some number or other of pieces, the exact number being left indeterminate.
Conclusion and Metaphilosophical Upshot
And so it might be like this: nature in itself is animated by an intrinsic immanent teleology or intentionality below the level of conscious mind, an intrinsic (as opposed to derivative) purposiveness which is present in nature all along, but which becomes conscious only in us. This intrinsic and ubiquitous pre-conscious teleology or purposiveness suffices to ground the cognitive reliability of our faculties, and in such a way as to make it rational for us to trust their deliverances. For on this scheme, there is nothing fluky or accidental about mind. Mind is king and it is there all along. And this without any assistance ab extra from God, and of course without any constructive 'worldmaking' nonsense of the Goodmanian sort. (Allusion to Nelson Goodman, Ways of Worldmaking). We also avoid the eliminativist Unsinn of Daniel Dennett the scientistic sophist.
I am limning the metaphysical scheme presented by Thomas Nagel in his Mind and Cosmos, an overview of which you will find at my Substack site.
Nagel's panpsychist immanentism no doubt has it own flaws, as any decent aporetician ought to suspect. But Nagel's proposal does challenge any quick acquiescence in the design argument for God sketched above.
And so I come around once again to my oft-made meta-philosophical claim that in these metaphysical and theological precincts (and not just here) there are no 'knock-down' arguments, no arguments that are rationally compelling (rationally coercive, rationally inescapable, philosophically dispositive, pick your favorite phrase).
Let the dogmatists howl.
The dogs bark, the caravan passes: it ürür, kervan yürür.
Along the Silk Road, headed East.
