Question from Josh:
How can atheists be sure of the reliance of their cognitive faculties?
As Descartes and Plantinga proved, if naturalism is true, there cannot be reliance on our cognitive faculties. Only if our senses and brain were designed with the PURPOSE of revealing us the world, we can have such reliance upon truth values.
So, how can an atheist be sure of what her senses tell, if they were produced by blind evolution?
Can naturalists, evolutionists and atheists alike, respond properly to Plantinga’s EAAN [Evolutionary Argument Against Naturalism]?
Answer by SmartLX:
They can indeed respond, and they frequently have. The reference section of the Wikipedia page on EAAN (for ease of reading, imagine I’m pronouncing it like the first name Ian) contains links to no less than a dozen academic responses, many of which are summarised in the article. Just Google “EAAN response” and you’ll be up to your neck in atheists. I’ll now contribute my response to your own expression of the argument.
Not only can we not be sure of what our senses tell us, we can be pretty sure that our senses are lying to us, and often. We all have literal blind spots, which we can demonstrate to ourselves by making small marks on paper disappear while moving our eyes. Our mental faculties are just as dodgy; we forget, we hallucinate, we jump to conclusions. That what we perceive is nowhere near reliable isn’t news to anyone, so deliberate design isn’t needed to explain any kind of incredible accuracy because it’s just not there.
EAAN makes a bolder claim: that without a system deliberately designed to perceive the world, we cannot know whether anything is true outside of our own existence. As bold as this sounds, it’s easily outdone by the idea of “hard solipsism”: that there is no sure way to know whether anything we perceive is real, regardless of the origin of our senses. Even if God made us, perhaps He made us as brains in jars having dreams of each other. So even claiming that our senses perceive some of reality because they were designed falls at the first hurdle, because maybe we don’t perceive ANY of reality. With this uncertainty, arguing that our senses are designed to be accurate because that means we’re happily living in the real world is an appeal to consequences, a common logical fallacy.
With that avenue explored, let’s assume for a while that we do perceive some real things which help us to live our lives together in a real world with real consequences. Why would this automatically mean that our senses were designed to work? Is it entirely impossible that they simply developed, by natural selection for example, precisely because accuracy confers practical benefits which translate into survival advantages? Quite the contrary, it’s impossible to rule out even if you think it’s unlikely.
EAAN takes this into account though, and makes the point that without assuming deliberate design we can never be sure that our senses are at all reliable. Well, hard cheese. We’ve known that ever since the claim of solipsism, because we haven’t been able to effectively refute that either. That our senses are reliable has always been an assertion. This assertion is constantly backed up by sensory evidence, such as feeling that an object is there when we reach out to grab it, but since the same senses are picking up this evidence it only supports the idea that the world we perceive is consistent, whether or not it’s real. However, this is enough for most of us to confidently live our lives AS IF we’re in a real world, and control our destinies within that world as best we can. Whatever our true circumstances are, it’s easy enough to imagine that our senses could naturally develop at least this consistency. If instead you believe in design, you dismiss all of the little uncertainties in favour of one big uncertainty, and good luck to you.
Josh, this response is not worded in the same formal terms as the actual argument, and there’ll be a great deal about the complete form that I haven’t addressed, but as I said I’m addressing your specific expression of it. As shown, there are plenty of other responses which do the terminology, the probability expressions, the whole enchilada. If there’s an unexplored aspect of the argument you think strengthens it, then I’ll wonder why you didn’t include it in the first place but go ahead and add it in a comment (in your own words, so I at least know you understand it yourself).