To look at a star by glances..

I’ve blogged before about my love of classic detective stories and about the intriguing historical connections between astronomy and forensic science. However, I recently finished reading a book that gave me a few more items to hang on that line of thought so I thought I’d do a quick post about them today.

I picked up a copy of The Suspicions of Mr Whicher by Kate Summerscale when I saw it in a stack of discounted books in Tesco a few monthsa go. I thought it might be mildly diverting, so I bought it. It turned out to be a fascinating read. I won’t spoil it by telling too much about the story, but it is basically an investigation into the circumstances surrounding a real-life murder that happened on 30th June 1860. The case involved a truly shocking crime, the brutal slaying of a young boy, but it also offers great insights into the history of the Criminal Investigation Division (CID) of the Metropolitan Police, which was based at Scotland Yard from about 1842 onwards. Mr Jack Whicher was the Yard’s most celebrated detective at the time, but this crime went unsolved until, about five years later, the perpetrator walked into a police station and confessed to the murder.

In telling the story, Kate Summerscale touches on a lot of fascinating social history. For example, I had never realised that in the early days of the CID people were strongly opposed to the idea that plain clothes policemen might be snooping about so all detectives were required to wear their uniforms even when off duty! It’s also fascinating to note that the rise of the true-life detective coincided with the rise of the detective story in popular fiction.

Edgar Allan Poe’s short story The Murders in the Rue Morgue, generally accepted to have been the first real detective story, was first published in 1841. Even in this first example of the genre, we find a clear parallel being drawn with astronomy by the detective Dupin:

Thus there is such a thing as being too profound. Truth is not always in a well. In fact, as regards the more important knowledge, I do believe that she is invariably superficial. The depth lies in the valleys where we seek her, and not upon the mountain-tops where she is found. The modes and sources of this kind of error are well typified in the contemplation of the heavenly bodies. To look at a star by glances–to view it in a side-long way, by turning toward it the exterior portions of the retina (more susceptible of feeble impressions of light than the interior), is to behold the star distinctly–is to have the best appreciation of its lustre–a lustre which grows dim just in proportion as we turn our vision fully upon it. A greater number of rays actually fall upon the eye in the latter case, but in the former, there is the more refined capacity for comprehension. By undue profundity we perplex and enfeeble thought; and it is possible to make even Venus herself vanish from the firmament by a scrutiny too sustained, too concentrated, or too direct.

No less a figure than Charles Dickens also had thoughts along these lines. In 1850 in a short article called A Detective House Party, he compared detectives with the astronomers Urbain Leverrier and John Couch Adams who in 1846 had simultaneously discovered the planet Neptune. Dickens died in 1870 leaving his own detective story The Mystery of Edwin Drood still unfinished but his good friend Wilkie Collins did a great deal to establish the literary genre of detective fiction with The Moonstone and The Woman in White. Indeed, in the mid-19th Century the idea of detection seems to have imprinted itself on fields as diverse as natural history and journalism as well as astronomy.

The point that strikes me is that astronomy and criminal investigations are primarily observational rather than experimental. One has one Universe and one scene of the crime. In both disciplines the task is to reconstruct what happened from what is seen and what is not.

The detective instinct, brightened by genius, marked unerringly the place of that missing planet which no eye had seen, and whose only register was found in the calculations of astronomy.

I use metaphors like this quite often in popular lectures, and they seem to go down quite well. On the other hand, I’ve often had my leg pulled for admitting to watching TV programmes like CSI: Crime Scene Investigation. Admittedly, the characterisation is very weak and the plots often ridiculously far-fetched. However, these stories do at least attempt to portray something of what the scientific method is about. And that’s something that not many so-called science programmes bother to do these days.

3 Responses to “To look at a star by glances..”

  1. Anton Garrett Says:

    Absolutely. The hard part of both astronomy and detective work, where genius is involved, is hypothesis creation. Anybody can test a given hypothesis against the data easily enough in either field.

  2. telescoper Says:

    Anybody should be able to test a given hypothesis, but you’d be surprised how many scientists can’t even do that properly!

  3. Anton Garrett Says:

    OK Peter, here’s a teaser for you, given that Bayesian reasoning is supposed to mimic how the brain works when it is doing its job properly. Bayesian reasoning can only test one hypothesis *against another*. So what is our brain doing in circumstances when it has only one theory – a theory which it has hitherto accepted but then starts to reject as technology allows the exploration of further regions of parameter space? For instance, a Newtonian physicist prior to relativity might have happily observed a good fit of the energy-momentum relation to quadratic, but noticed that the fit gets progressively worse at speeds that are a significant fraction of the speed of light and concluded that Newton was wrong. What is that physicist’s brain doing that Bayesian reasoning isn’t, and how can it be incorporated into the Bayesian framework?

    Put another way, if you have only one theory then in what circumstances – and why – is it not rational to accept that theory and assign all deviations to noise, whatever the data?

    I am wondering if the brain does an implicit 1-parameter generalisation of the theory and an intuitive Ockham analysis which prefers that generalisation. But the brain only really does pattern recognition. (How?) A similar challenge is to model how the brain can predict in the absence of any theory whatsoever. Pre-Galileo, everybody knew that it took longer for a body to fall farther, even though the quadratic form of the height-time relation was unknown.

    Anton

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: