Two arguments on the limits of reason

Trying to live and think as a rational human being is my goal. But perhaps the project is doomed. I’ve been reading David McRaney’s book You Are Not So Smart, which playfully (but no less convincingly) undermines the cherished belief that we are rational human beings.

For example, he writes about priming – “When a stimulus in the past affects the way you behave and think or the way you perceive another stimulus later on” – which leads us to an idea about how our thoughts maintain mental equilibrium without necessarily being grounded in reason, called the adaptive unconscious; and eventually, with a little research from Wikipedia, we find ourselves at the introspective illusion:

The introspection illusion is a cognitive illusion in which people wrongly think they have direct insight into the origins of their mental states, while treating others’ introspections as unreliable. In certain situations, this illusion leads people to make confident but false explanations of their own behavior (called “Causal theories”) or inaccurate predictions of their future mental states.

In short, we cannot be sure of where some of our mental states – and the beliefs, ideas, thoughts and feelings that accompany them – originate. The following experiment illustrates the potential for people to lack insight into their preferences and the ability, in the absence of a rational explanation, to ‘confabulate’, or invent, the reasons for doing so:

Subjects saw two photographs of people and were asked which they found more attractive. They were given a closer look at their “chosen” photograph and asked to verbally explain their choice. However, using sleight of hand the experimenter had slipped them the other photograph rather than the one they had chosen. A majority of subjects failed to notice that the picture they were looking at did not match the one they had chosen just seconds before. Many subjects confabulated explanations of their preference. For example, a man might say “I preferred this one because I prefer blondes” when he had in fact pointed to the dark-haired woman, but had been handed a blonde. These must have been  confabulated because they explain a choice that was never made.

The large proportion of subjects who were taken in by the deception contrasts with the 84% who, in post-test interviews, said that hypothetically they would have detected a switch if it had been made in front of them. The researchers coined the term “choice blindness” for this failure to detect a mismatch.

In this case, any perceived (by the subject) rational explanation for making their choices was undermined by the sleight of hand. Despite this, most subjects didn’t notice; and of those, they offered what was to them a rational justification for their choice. One explanation for our difficulties with understanding our preferences, for example, is the sometimes unknown significance that objects possess for us. As McRaney suggests:

Just about every physical object you encounter triggers a blitz of associations throughout your mind. You aren’t a computer connected to two cameras. Reality isn’t a vacuum where you objectively survey your surroundings. You construct reality from minute to minute with memories and emotions orbiting your sensations and cognition; together they form a collage of consciousness that exists only in your skull. Some objects have personal meaning, like the blow-pop ring your best friend gave you in middle school or the handcrafted mittens your sister made you. Other items have cultural or universal meanings, like the moon or a knife or a handful of posies. They affect you whether or not you are aware of their power, sometimes so far in the depths of your brain you never notice.

When we interrogate the extent to which we are rational beings, the perceived dichotomy between religious belief and reason needs to be renegotiated. Julian Baggini, in his ‘Heathen’s Progress’ blog, argues that those who believe themselves to be rationalist need to recognise the ways in which their reason might be compromised:

Humanism [secular rationalism] is faced with the bind that its existence depends on maintaining a tension between finding what is good and worth celebrating in the human and having the intellectual integrity to see our species warts and all, which means being open to the possibility that we are not as great as we’d like to think we are.

‘Not as great as we like to think we are’ chimes with the notion of the illusion of introspection and our ability to make rational decisions, as we’ve seen in the ‘choice blindness’ example above. He goes on:

No self-respecting humanist can fail to have “doubt over humanity”, and although that need not occlude all the light, it is a dark cloud we have to live under.

Here’s where it gets interesting. The doubt over humanity that is an inevitable corollary of secular humanism cannot be neatly contained and eventually it spills over into doubt abut the capabilities of human reason. Indeed, the more you know about how the human mind works, the less reason we have to trust our rational capacities. For instance, Alvin Plantinga’s evolutionary argument against naturalism claims that secular reason leads to evolution, but evolution removes any reason we might have to trust secular reason. There is no reason to believe that a brain that evolved to help us survive in the pleistocene is a reliable tracker of truth. Darwin himself had this concern, writing that “the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy”.

Baggini summarises:

What all this suggests is that in practice there is no neat distinction between the logical and the psychological. Those who attempt to use pure reason cannot expect to succeed, while those who willingly allow psychological factors to affect their reasoning may be being more self-aware about their rational capacities than those who do not.

Despite this, we need not throw out the rational baby in the bath water of reason. Even if we are not completely rational beings and do not possess the kinds of intellects and cognitive apparatus to make us what we might sometimes aspire to be – rational human beings – we must continue using reason, whilst noting its limitations:

Kierkegaard saw the limits of reason as themselves a reason to make irrational leaps of faith. In a more modest form, his insight could help explain the rational non-rationality of much religious belief. […] We choose faith so as not to be lost, because the alternative, reason, cannot enable us to find ourselves.

As an atheist, I’m not convinced by this. People who have a point are often nonetheless wrong, and often it’s precisely because of that point that they go wrong. Reason has its limits but we need to go right up against them, and for my money faith sees these limits and gives up on reason too soon.

Nonetheless, the mere fact that a serious argument can be made against the coherence of relying on human reason alone not only gives us atheists a way of understanding religion more sympathetically, it also suggests that the limits and role of reason has been a relatively neglected area of debate between believers and non-believers.

In rational discourse, it is not enough to simply immerse yourself in the ideas and arguments of others, but to understand – where possible – the extent to which your ideas are influenced by unconscious processes. You must know thyself as well as know thy enemy.


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