Common Sense?

 

In discussion over an engaging post about altruism by Richard over at Pixnaps he introduced an interesting point about common sense.

Richard: It involves rejecting our common-sense understanding of human action, and implies that we are engaged in massive self-deception.

IM: Definitely, why would you suppose that common-sense understanding of the human mind in reference to how we act just happens to be the best and most accurate model.

All else being equal, it counts against a theory if it is counter-intuitive. Similarly if it implies that most of our beliefs are false, that we are engaged in massive self-deception, etc. This isn't a decisive objection, of course, but such uncharitibility does count against a theory. (The Brain-in-a-Vat hypothesis can account for all the data, but we reject it because it implies that all our common-sense beliefs are false. Simple realism is an alternative theory that serves much better in this regard. I have two hands, and I have other-regarding desires. We prefer theories that don't contradict these core beliefs.) So the onus is on the theory's proponent to show there is some advantage which makes this cost worth bearing.

I think that it is probably right in one sense that the counter-intuitive nature of a theory counts against a thoery but that this is outweighed by explanatory power.

The reason we develop theories is to grant an understanding of reality. If one theory gives an account of reality that confirms our common-sense beliefs and intuitions then it is far more palatable than one that requires us to reject our previously held notions and assumptions about the world and ourselves.

The danger here however is that because of its palatability we may search for theories to confirm our preconceived notions and ideas and our perspective may therefore skew.

Our aim and intent should always be to seek out those theories which grant the most explanatory power’. What does this mean? Well take the following passage from Shakespeare’s Macbeth:

Macbeth: Out, out, brief candle! Life's but a walking shadow, a poor player That struts and frets his hour upon the stage and then is heard no more. It is a tale Told by an idiot, full of sound and fury, Signifying nothing.

1. Now one interpretation could be that in this line Macbeth is describing an actor whose name is ‘Life’ and only had one hour playing a part upon the stage before loosing his voice forever.

2. Another is that it is referring to the fragility and absurdity of life, demonstrating Macbeth’s morose reaction to the news that Lady Macbeth has killed herself.

Now neither one of these interpretations/theories are any more valid than the other, they are both logical in the sense that they are semantically clear and follow from the original passage. What differs between them is their explanatory power, interpretation two is clearly far more powerful when considered in the context of the scene and the play and enables the reader to gain an intimate understanding of the character Macbeth. Interpretation two makes the reader why Macbeth would bring up such an irrelevant anecdote at a time like this.

Equally, Copernicus theory of the orbits of heavenly bodies in our galaxy granted far more explanatory power than the alternatives of his day even though it required people to suppose that they were victims of a massive self-deception at the hands of the Church who were convinced of the veracity of the account of Genesis.

The brain in the vat hypothesis may explain why some people appear to have advanced telekinetic capabilities but it disables us from understanding how we interact with reality and raises further questions of how we came to exist in vats. This is why we reject it, or at least this is why we should reject it.

Why should the counter-intuitive nature of a theory count against it? Not because of the effort involved in adjusting long-held intuitions, but because common sense holds a great deal of explanatory power.

I think that common sense intuitions are developed through an evolutionary biological manner. That if are brains are formed at the same time as our bodies it makes sense that we are intuitively attracted to features that happen to be indicators of health in our mates. It makes sense that we are intuitively fearful, or less empathetic with foreigners who look different from ourselves. It makes sense that we can easily conceive of the idea of ten things but not of a trillion things.

Along this view it would also make sense that our common sense grants us very simple ideas with great explanatory power but with no ability to discover the inner mechanics of reality that may link everything together. It makes sense that we are engaged in a massive self-deception because these intuitions are based upon the interface between an evolving primate and the world.

In this sense, I propose that counter-intuition does not detract from a theory at all. Whereas limited explanatory power and over-complexity does.