On what purely naturalistic grounds can an atheist judge something as either morally good or evil?
I have touched on this one before, but will lay the ground rules out again:
“Naturalistic grounds” is the wrong place to start, it’s committing the Naturalistic Fallacy, the notion that what “is” is necessarily good (or not). The natural world doesn’t have morality. Just as the iceberg the Titanic slammed into had no intention to cause trouble for the ocean liner’s passengers, no matter how creepy it may seem to us (as beings capable of moral perception and reasoning) a parasitical wasp injecting its young to feed on a paralyzed host grub isn’t doing “good” or “evil” in that action, it’s just being a wasp, no more conscious of its actions that your toaster browning an English muffin.
But if a sentient being were to do the same thing, then you’re in Dr. Mengele creepy territory.
The moment a being is capable of reflecting on its actions, at that point it faces the issues of “should” or “ought” and hence whether those actions are “good” or “evil.” This is a realm of normative philosophical belief which are “undecidable” in the sense that you cannot lay out a truly slam-dunk “proof by sufficient evidence” argument of a sort that governs the decidable propositions of the empirical domain of knowledge that science can settle. My NOMA revisited postings went into that in greater detail, and there’s a general summary of this at here.
It may be telling us something deep about people’s desires and foibles in this area that the NOMA issue is just as annoying for many atheists as religionists. People don’t always take kindly to being told there are lines not to be crossed, barriers they cannot penetrate, requiring them to respect the limits of their evidence and reasoning. Well, tough nuggies.
Now people who govern their beliefs about good or evil actions based on a set of religious proscriptions may think they have the secret key to truth, but that depends of course on whether those rules are in fact morally defendable. Just pointing to the list and saying, “this is what the God wants, and that settles it” doesn’t actually settle it, as Plato pointed out in his Euthyphro dialogue. Is what the God recommends actually good, or is it just the God’s command whim? Thou shalt not eat asparagus!
Unless there is an external absolute measure to judge, of course, in which case the atheist is just as entitled to accept that and skip the middle man of the recommending religious revelations. Religious apologists can wriggle out from the Euthyphro Dilemma by positing that God by its very nature can’t avoid recommending the true and good and moral, which is OK to argue but it is laminating yet another assumption on the problem: (1) existence of an absolute moral framework + (2) the god of your choice + (3) specifying that the god of your choice has a nature that guarantees it will pick the right and true choices from the list of independent absolutes over which it otherwise has no say or control.
This problem isn’t unique to moral reasoning, by the way. Though there are some religionists who think their god makes mathematics true, and so 1+1=2 and not some other number just because the god wants it that way, I would contend that no deity can ever make 1+1 not come out 2. And in any case, I wouldn’t want to let such a believer do your tax returns.
Now there’s a second pitfall in the religious argument on good and evil, and its that most religious traditions carry a heap of historical baggage to suggest that they don’t quite practice what they preach, meaning the list of moral absolutes seems to be a relativistic one of picky-choosy. In the God of Abraham case, you’ve got those repugnant rules on how to treat your slave in Exodus 21, and the many instances of “yes, I commanded you guys not to kill, but that doesn’t mean you’re not supposed to kill people when I tell you to” (Amalekites etc).
The inherent ambiguity of human moral reasoning (whether done by atheists or religionists) turns partly on the fact that (as we now know through scientific investigation) we humans have at least two independent brain systems that contribute to our deciding what we consider good and bad. One of them is a snap judgment emotion based system spinning off our amygdala (that tiny reptile brain piece we retain and co-opted over hundreds of millions of years of natural evolution into mammals and primates and us). Another system is a slower more reasoned based system that employs that frontal cortex that expanded so much in primates and us. Neither of these systems evolved to do moral reasoning per se, and are still not dedicated to that task exclusively. In that sense moral reasoning can be considered what Stephen Jay Gould (the original NOMA guy) regarded as a “spandrel” (a natural system arising in a sense inadvertently from base systems doing something else).
The “Bridge Problem” (where the person has to decide to intervene or not to prevent some people from getting run over by a train, but at the price of causing trouble for a smaller number of people) is just one of the ways psychologists have approached measuring this issue of how our minds resolve moral issues, and how changing the circumstances even slightly (throwing a switch to divert the train to run over one person instead of five, compared to actively throwing the one person off the bridge to prevent the train from running over the five further down the track) can prompt our brains to arrive at very different decisions on what is essentially the same issue (cause the death of one person to save five). And that’s because those differing framings of the problem trigger differentially strong reactions from those two competing brain systems we now know we use for moral reasoning.
So the question about “purely naturalistic grounds” pertaining to moral reasoning is presupposed to mean that the “purely non-naturalistic grounds” of the religious commandment argument somehow settles the question in a way the first doesn’t. That is a false dichotomy. Religious presumptions about good and evil act as a comforting blanket to make us feel all warm and certain when it has only covered over the (still natural) brain mechanisms that come into play to make the decisions of life. Non-religious people have to grapple with the same issues, and lay out their philosophical reasons for believing their actions are or are not good or bad.
Atheists (such as yours truly) can employ lots of empirical tools to help us decide our philosophical belief on moral questions (and I would wager of religious people use such tools too, tempering their supposedly absolute moral compass). William James’ Pragmatism is helpful here, looking at the history of what has happened based on what people have done given their believing one way or another. The events of Inquisitions and Soviet gulags should give everyone pause on any attempt to apply some rigid ideology (Christian or Marxist, religious or atheist) to human conditions. Here the Golden Rule seems especially apt (as I wouldn’t want to be burned at the stake for heresy or worked to death to achieve the Socialist Utopia, so then should no one have that happen to them), likely explaining why most every culture has some version of it undergirding all the sundry revelations of their otherwise contradictory deities. One might also toss in the advice of the High Lama to “be kind” from “Lost Horizon” while we’re about it.
All of us (religious and atheist) are in the same boat, having to figure out what our moral destinations are and how to set course there. No naturalistic or divine charts can simplify this problem for us. The scientifically minded know more about how our brain sails react to a particular wind direction, but not even a divine puff can make those winds go away. That’s why moral reasoning is still as tough today as it was in Plato’s day (and will remain so for all self-aware beings everywhere in the universe). Its the “nature” of the problem.