Posted by: dacalu | 5 October 2013

Naturalism VII (The Reason Critique)

This is the sixth post in a series on Naturalism, the idea that the world is wholly made up of natural or physical objects and events.  The series starts here.  After exploring what naturalism could mean, I gave it the most sympathetic treatment I could and am now going to present why even that fails from my perspective.  The following argument is taken from CS Lewis’ book Miracles.  The responses draw on Daniel Dennett and Konrad Talmont-Kaminski.  They treats this far more fully there than I can here. 

The Reason Argument

If empirical data are considered to be reliable indicators of the natural world (which they may not be under naturalism) we still have to think critically about how we move from data to theories about the natural universe and what theories may be considered laws.

Cartesian dualists are allowed to differentiate between valid conclusions and natural dispositions.  Valid conclusions follow from true premises (in our case data) and sound arguments.  The soundness of arguments arises from their strict correctness every time they are used.  That is, one cannot be mistaken in using them, because a priori reasoning supports their worth.  Remember, this is a Cartesian perspective, with minds abstracted from matter and living in a separate realm of existence.  Natural dispositions come from the inclinations of our bodies, uninfluenced by the intent of Cartesian minds.  As implausible as this distinction may sound in the modern context, our system of reasoning is quite firmly founded on it.  To this day, we distrust “intuitions” until they have been vetted by critical analysis.  Note, intuitions were and are considered valuable, but only as a starting point.

As naturalists, we are unable to invoke the mind/body divide in order to differentiate intuition and emotion from reason.  Neurology, economics, and evolutionary psychology all concretely and definitively prove that our reasoning process is integrally tied to the physical processes that underlie it and, therefore, in no case can biases be definitively eliminated.

Instead of “pure reason” we are left with evolved algorithms and heuristics for turning sensory inputs into behavioral outputs.  While we may consider these processes reliable, or at least the best we have, we must admit that they lack the level of certainty our Enlightenment predecessors thought.  While we can imagine some survival/reproduction value in knowing what is really out there beyond ourselves, we see that that criterion replaces “truth” as the end of our inquiry.

Put another way, strict naturalism in explaining human reason suggests that the faculty for mapping reality into our internal models was an adaptation.  Insofar as it is optimized, it will be optimized for our survival and not optimized for accuracy.  It is in no way difficult to imagine scenarios in which accurate mapping would decrease survival and those turn out to be some of the very same biases we see we have.  Our heuristics overestimate the frequency of rare risks in order to turn our awareness to issues we can avoid.  They encourage us to be overconfident in our beliefs when sufficient data is unavailable and worrying would be a waste of energy.

Naturalism suggests our faculty of reason is neither more nor less than a mechanism for furthering our traits.

The Evolutionary Rebuttal

This may be good enough, or at least it may be the best we have.  It is apparent that we do not make decisions simply, but usually involve a complex – if not necessarily conscious – process of weighing different inputs.  When energy is abundant, we have the ability to use that energy to engage in conscious assessment and incorporate the reasoning skills of others.

Indeed, humans seem uniquely capable of group problem solving in a way that has allowed us to dominate life on the planet.  The construction of consistent models across large groups of people facilitate that activity.  Why wouldn’t we evolve consistent reasoning?  Accuracy may even be conducive to consistency.

On one hand, there seem to be strong evolutionary forces which promote lying to one another and gaming the system.  On the other hand, those same forces should lead to a signalling arms race in which we increasingly know how to lie and how to detect lies.  Ground truthing through accurate models may be a successful strategy.


To my mind, this critique ends up something of a wash.  There seem to be sufficient naturalist explanations to make “reason” compelling, as long as we give up enlightenment notions of justification.  There is no more knowledge under this model, only beliefs.  Even the ability to mark those beliefs as true suffers a serious blow.  They are, rather useful.

I think honest naturalists can and should be satisfied with useful beliefs.  They must, though, under this rubric, give up the notion of ontological naturalism as a universal or exclusive claim.  There remains no way to deductively show that non-natural things do not exist, only ad hoc arguments that specific non-natural claims have no utility.  And in those cases, a sufficient reply will be: it works for me.

Notably, Christianity and Islam are apparently highly successful strategies in an evolutionary sense.  Belief in a personal God has been selected for historically and still appears to be correlated with a higher number of offspring.  Non-naturalism, specifically theism, works.

I find myself far more inclined to be a Christian – a fairly conservative Christian at that* – under strict naturalism than I would be as an idealist.

This leaves us with a rather uncomfortable dilemma.  What does it mean to have a belief system optimized for survival if you wish to argue for beliefs that are not survival optimal?


[*For promoting survival and reproduction, I’d be inclined to choose a belief system with a strong community structure, high membership costs, clear behavioral rules, and extensive dogma, to ensure communal support and avoid mental energy devoted to areas other than community and person success.]


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