When a group of Australians was asked why they believed climate change was not happening, about 36% said it was “common sense”, according to a report published last year by the Commonwealth Scientific and Industrial Research Organization. This was the most popular reason for their opinion, with only 11% saying their belief that climate change was not happening was based on scientific research.
But what do we mean by an appeal to common sense? Presumably it’s an appeal to rationality of some sort that forms the basis of more complex reasoning. The appeal to common sense, however, is usually nothing more than an appeal to thinking that just feels right, but what feels right to one person may not feel right to another. Whether it feels right is usually a reflection of the world view and ideologies we have internalised, and that frames how we interact with new ideas. When new ideas are in accord with what we already believe, they are more readily accepted. When they are not, they, and the arguments that lead to them, are more readily rejected.
We often mistake this automatic compatibility testing of new ideas with existing beliefs as an application of common sense, but, in reality, it is more about judging than thinking. As Nobelist Daniel Kahneman notes in Thinking Fast and Slow, when we arrive at conclusions in this way, the outcomes also feel true, regardless of whether they are. We are not psychologically well equipped to judge our own thinking.
We are also highly susceptible to a range of cognitive biases such as giving preference to the first things that come to mind when making decisions or giving weight to evidence.
One way we can check our internal biases and inconsistencies is through the social verification of knowledge, in which we test our ideas in a rigorous and systematic way to see if they make sense not just to us, but to other people. The outstanding example of this socially shared cognition is science.
That does not mean that individuals are not capable of excellent thinking, nor does it mean no individual is rational. But the extent to which individuals can do this on their own is a function of how well integrated they are with communities of systematic inquiry in the first place. You can’t learn to think well by yourself.
In matters of science at least, those who value their common sense over methodological, collaborative investigation imagine themselves to be more free in their thinking, unbound by involvement with the group, but in reality they are tightly bound by their capabilities and perspectives. We are smarter together than we are individually, and perhaps that’s just common sense.
