Taylor begins by asking us to ... suppose you are traveling by train through the UK and, peering out the window, you see an arrangement of stones in a pattern that looks like this: THE BRITISH RAILWAYS WELCOMES YOU TO WALES. You would naturally assume that the stones had been deliberately arranged that way by someone, in order to convey the message that you are entering Wales.Random, mindless processes do not and cannot convey a message, of course, so if one believes the stones mindlessly fell into the pattern Taylor describes then one cannot believe that they convey a message. Feser continues:
Now, it is possible in theory that the stones got into that arrangement in a very different way, through the operation of impersonal and purposeless natural causes. Perhaps, over the course of centuries, the stones gradually tumbled down a nearby hill, and each one stopped in a way that generated just that pattern.
This is, of course, extremely improbable, but that is irrelevant to Taylor’s point and he allows for the sake of argument that it could happen.
Taylor’s point is rather this. Even if you could reasonably entertain the latter possibility, what you could not reasonably do is both accept it as the correct explanation of the arrangement of stones and at the same time continue to regard that arrangement as conveying the message that you are entering Wales.
The arrangement could intelligibly be conveying that message only if there is some intelligence behind its origin, which brought it about for the purpose of conveying the message. If, instead, the arrangement came about through unintelligent and purposeless causes, then it cannot intelligibly be said to convey that message, because it could not in that case intelligibly be conveying any message at all.
I hasten to emphasize again that Taylor’s point has nothing whatsoever to do with probabilities, and in particular nothing to do with how likely or unlikely it is for arrangements of the kind in question to form via natural processes. He allows, for the purposes of the argument, that that could happen.The stones by themselves have no meaning apart from a mind that arranged them in the pattern they're in. If no mind was involved, if the pattern arose through natural, physical processes like wind and erosion, the pattern would have no meaning at all.
His point is rather that, no matter how complex and orderly are the arrangements of physical components that might be generated by purely impersonal and purposeless natural processes, they could never by themselves generate something with intentional or semantic content. (This way of putting things is mine rather than Taylor’s.)
This is not a point about probabilities, but rather a conceptual and metaphysical truth. [Stones have no] inherent connection with any semantic content we might decide to convey through them. The content they might have must derive from a mind which uses them for the purpose of conveying such content.
Delete such a mind from an explanation of the arrangements of stones..., and you delete the semantic content along with it.
It would not be about anything, and you would have no reason to trust its accuracy or truth. But what does this have to do with the Intelligent Design of our brains? Feser goes on:
Taylor then asks us to consider our perceptual and cognitive faculties. These, too, we take to have intentional or semantic content. We have visual experiences such as the perception that there is a cat on the mat, auditory experiences such as the perception that someone has just rung the doorbell, and so on. We have the thought that there will be rain tomorrow, the thought that two and two make four, and so on.Feser goes on to consider several objections to Taylor's argument and shows that they all fail.
We take it that a visual experience like the one in question is not merely the presentation to the mind of an array of colors and shapes, and that the auditory experience in question is not merely a sequence of sounds, but that the experiences convey the messages that the cat is on the mat and that someone is at the door.
Of course, we might be misperceiving things, but that is not to the point. The point is that the experiences do convey those messages, whether or not the messages are accurate. Similarly, we take it that when we “see” or “hear” a sentence like “There will be rain tomorrow” as it passes through our imaginations, this is not a mere string of internally apprehended sounds or shapes, but conveys the meaning that there will be rain tomorrow.
Now, Taylor is happy to allow for the sake of argument that, as with the arrangement of stones you see out the train window ... our sensory organs and neural structures may have arisen through entirely impersonal and purposeless natural processes, such as evolution by natural selection. He is not interested in challenging the probability of such explanations.
The arrangement of stones you see out the train window ... seem purposeful, but Taylor allows that that may be an illusion. Similarly, he allows that our sense organs could seem to have a purposeful arrangement and yet be purposeless for all that.
His argument has nothing at all to do with how likely or unlikely it is that the appearance of purpose could arise from purposeless impersonal process.
What he is concerned about instead is the case where we suppose our sense organs and neural processes to have genuine purpose, and in particular where we suppose our perceptual experiences and thoughts to have genuine intentional or semantic content. And he wants to make a point that parallels the point he made about the arrangement of stones.
We could take the deliverances of our sense organs and neural states to have genuine intentional or semantic content. Or we could take those organs and states to have arisen through entirely impersonal and purposeless natural processes. What we cannot reasonably do is both of these things at once.
In particular, we cannot intelligibly both take these cognitive faculties to have arisen through entirely impersonal and purposeless processes and at the same time regard them as having genuine intentional or semantic content – as conveying any message about cats on mats, the ringing of doorbells, rain tomorrow, or anything else.
Delete mind and purpose from your account of the origin of the arrangement of stones, and you delete any semantic content along with them. Similarly, if you delete mind and purpose from your account of the origin of our cognitive faculties, then you delete any intentional or semantic content along with them. You can have one or the other account, but not both.
Now, our cognitive faculties do in fact have intentional or semantic content. We really do have perceptual experiences with the content that the cat is on the mat, thoughts with the content that it will rain tomorrow, and so on.
Since this is intelligible only on the supposition that our cognitive faculties originated via some mind and its purposes, there must be some intelligent being that brought us about with the aim of having our cognitive faculties convey to us information about the world around us.
To summarize: Either our cognitive faculties were designed by a mind or they arose purely naturalistically through some mindless evolutionary process. If they arose through a mindless process then, like the rocks on the hillside, they can have no meaning, there's no message to be gleaned, and we'd have no reason to trust them or any of the ideas they produce.
If we think, on the other hand, that our cognitive faculties are generally reliable and that the ideas they produce do have meaning (intentionality) then we have to conclude that they're not the product of mindless forces but are instead the product of an intentional agent who designed them for the purpose of discerning meaning in the world.
Naturalism fails to give a plausible account for how our minds can reliably detect meaning, whether it's in our sensory observations (I see a tree in the yard, I hear a sweet melody, I smell a familiar scent) or in abstract ideas like my idea of free will or moral goodness).
If our cognitive faculties arose as a merely natural coincidence, then like the stones coincidentally rolling into the pattern, we have no reason to place any confidence in the ideas they produce, including, ironically enough, the very idea that they're the result of purely mindless processes.