Issue Two Online Extra: The Limits of Rationality: When Reason Falls Short of Itself By Steve Fuller

This article is part of the Online Extra section of Issue Two which you can read here.

Please note: This article was originally published on the original version of The New Idealist online in August 2013 before being added to this newly created site in July 2015.

Thoughts about ‘the limits of rationality’ normally spark images of things that get in the way of reason: emotions, bias, lack of evidence, etc. We rarely imagine that reason itself may fall short of its potential. Here I mean situations, always quite striking in retrospect, when something that we believed on independent, usually metaphysical, grounds prevented us from applying a line of argument to its logical conclusion. Such arguments typically have a mathematical dimension. Specifically they attempt to convert a difference in kind to one of degree.

For example, if we can measure moving bodies in the heavens and on Earth, why can’t we also measure the motions of people on Earth or, for that matter, the motions of whatever ‘spirit’ lurks in their bodies? Until the 19th century, the overriding objection was that people are qualitatively different from physical things. That metaphysical belief cast a pallor of moral corruption on anyone who would dare derive useful information from measuring or calculating the activity of human beings. The attitude lingers today, say, in the instinctive antipathy displayed by even quite learned people to economic appraisals of value. The political psychologist Philip Tetlock has coined the phrase ‘taboo cognition’ for this self-limitation of reason.

The ancient Greek logicians may have discovered taboo cognition when they pondered the paradox surrounding the style of argumentation we now call ‘slippery slope’. Thus, a full head of hair clearly makes one ‘hairy’. But suppose just a single hair is removed: Isn’t the person still ‘hairy’? And then you remove another, and another, and so on. Clearly, at some point, the person is no longer ‘hairy’ but ‘bald’ – but when? The general lesson learned was that once an absolute distinction such as ‘hairy’ versus ‘bald’ is turned into a continuum admitting of degrees of ‘hairiness’ or ‘baldness’, then intuitions relating to the values carried by the distinction – such as the difference between age and youth — start to be lost.

If the values at stake in being hairy or bald seem to be of purely cosmetic interest, then consider more potentially taboo topics such as the difference between ‘living’ and ‘non-living’ or, for that matter, ‘human’ and ‘non-human’. Once we admit the existence of intermediate cases, the significance of these distinctions is called into question. This helps to explain the heated controversies generated by, on the one hand, the prospect creating life in a test tube (increasingly called ‘synthetic biology’), and, on the other, the very idea that only a few genes separate humans from the other primates. Taken to the extreme, in full taboo violation, why not say that a rock is, in some sense, a ‘minimum’ form of life or a human is, in some sense, a ‘maximum’ form of matter?

The more that science has accepted the atomic world-view, which treats the qualitative differences between things as literally a surface appearance, the easier it has been to confront taboo cognitions. The overall effect of this intensive application of science has been to weaken the taboos, allowing reason to flow more freely. But it would be a mistake to think that science alone is capable of removing the barriers to our self-imposed restrictions on reason. In fact, poetry, of all things, may be seen as a harbinger to science in its taboo-busting function.

The Greeks originally understood poetic activity as the production of worlds with words, with all the potential for fraud suggested by such a definition. Nevertheless, this production requires a rather disciplined use of the imagination in which metaphor plays a central role. The cognitively striking feature of metaphor is its attempt to render two seemingly quite different things very similar, if not two instances of the same underlying reality. When a metaphor works, it opens up a new way of seeing the world. And as historians and philosophers have long known, once a metaphor has been sufficiently elaborated, it turns into an analogy, on the basis of which models may be constructed for scientifically comprehending and sometimes even controlling the world. Of course, these models harbour their own mental restrictions, but in this respect the war against taboo cognitions never ends.

Steve Fuller, Auguste Comte Chair in Social Epistemology, University of Warwick


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Issue Seven: The New Future Issue (Annual Special Edition)
Issue Six: The Autism Issue
Issue Five: The Doomsday Edition (Extreme Weather Special)
Issue Four: The Issue We’re All Talking About (Guest Edited by the actress Jodhi May)
Issue Three: Has Obama been corrupted by the machine?
Issue Two: IQ VS EQ – Is Emotional Intelligence what you need to succeed in the digital age?
Issue One: Downwardly Mobile? Will the next generation find it harder to reach the next level?

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