Propositional Knowledge and Tacit Knowledge: The Case of Tennis

Jonah Lehrer's Grantland piece on the physics of the tennis court is well worth your time if you're a tennis fan.  There's this, for example:

Although there still are no rules regarding the performance of tennis court surfaces — the game can be played on anything — in January 2008 the ITF began regulating the speed of courts used in Davis Cup tournaments. Because the host country gets to choose the tournament location, the new rules prevent the use of extremely slow or fast surfaces. So far, only one court — a clay surface in Croatia, used in a 2008 match against Brazil — has violated the regulations.

But Lehrer - a committed enthusiast of neuroscience - goes too far in reinforcing the distinction between propositional and tacit knowledge.  He points out - correctly - that that laws of tennis are ultimately the laws of physics but the speed of the game means that no player actually computes the trajectory of the ball using Newtonian mechanics while playing.  Instead the knowledge is displayed tacitly, in the way their bodies move, in the way they adjust their footwork and their racket motion, etc.  In Michael Polanyi's terms, this is tacit knowledge - knowledge that is expressed in action but is hard to express propositionally.  Lehrer chooses to illustrate this with the following example, which I found a little silly:

I met with the Caltech tennis team, arguably the smartest collegiate athletes in the country. (The average grade point average on the men's team is 3.73, which is one of the highest team GPAs in the NCAA. And these players are taking Caltech classes.) Despite this intellectual pedigree, the Caltech tennis players have struggled to win games: Last season, the men's tennis team went 1-16. Although many of the players can rattle off abstruse physics equations with ease, they all insisted that their textbook knowledge was not an advantage. "To be honest, it doesn't help at all," says Devashish Joshi, a freshman on the team. "I never think about science while playing."

Well, okay, if you say so.  But: 

"The top-ranked guys are all intuitive physicists," Hofmann says. "They know how the ball will bounce even if they can't explain why. This is what allows them to change their strategy based on the surface."

I don't want to de-emphasize how talented the top tennis players are.  But this makes it seem as though that that the only way of bringing propositional knowledge of physics into the game is if the players start calculating in their heads.  If you look at the role of knowledge in tennis, as simply something that gets displayed on courts, then, sure, there's only tacit knowledge.  But if you look at the world of tennis as a network (channeling Edwin Hutchins and Bruno Latour), then the propositional knowledge of physics comes into it at a number of different points:

Racket technology: There are actual physicists and material scientists who work on rackets.  They design rackets that are designed for different types of playing styles and different types of surfaces.  This is propositional knowledge as encoded into artifacts (in this case, the tennis racket), which then the players use. 

Coaching: Coaches help to get a lot of propositional knowledge on to the courts.  What's a "good" service action?  How much back-swing should you have while playing a stroke?  Is a long back-swing bad for grass?  A lot of this is backed up by actually thinking about physics and it gets incorporated into a player's game.  Novak Djokovic recently improved his service by making a "minor" adjustment - but this may have been key to his recent success because he is able to get some free points on his serve (69 more aces, according to the article). 

Playing strategy:  Recordings of previous matches are now easily available and allows players and their coaches to construct what is called a game-plan.  Game-plans are products of conscious reasoning and pattern recognition about an opponent's weaknesses and strengths - propositional knowledge and judgement at its best.  Of course, this is, in Lucy Suchman's famous formulation, like planning how to take your canoe into the rapids: useful only as a resource once you start playing.  But it is propositional knowledge, nevertheless, and is often the product of a whole network of people thinking: coaches, practice partners, managers, consultants, etc. as well as technologies like statistics, video recordings and such.


My point is that the propositional/tacit knowledge distinction is very useful.  But there are ways in which the two interact that is only visible at the level of networks.  In other words, knowledge, both propositional and tacit, is distributed - and while the best tennis players are definitely intuitive physicists, they are also beneficiaries of a lot of thinking that is careful and propositional - which is encoded into the artifacts they  use and the practices of coaching and training in their day-to-day life.

Anupama Chopra's Sholay: The Making of a Classic

I read Anupama Chopra's entertaining "Sholay: The Making of a Classic" yesterday - and I heartily recommend the book if you are interested in cinema, and especially, Indian cinema.  The book clocks in at an easy 190 pages and is easily read in one sitting.  Chopra's prose is breezy, and if the tone struck me as too adulatory in parts, there is enough detail about the process of film-making to make it well worth your while.  (The photographs - some black-and-white and a few color - are an added bonus.)

Perhaps the most surprising thing I learnt was that Sholay had an ending where the Thakur kills Gabbar - savagely - and then breaks down into tears - because revenge doesn't really get him back what he has lost.  Of course, since this was India in 1975, and even beyond that, an Emergency was in effect, the Censor Board found this piece of vigilante justice disturbing and insisted that the Sippys change the ending - that the police step in and stop the Thakur from killing Gabbar.  Already over the bduget, and desperate to release the film, the Sippys agreed.

It's Chopra's final lines that chilled me:

But apparently, somewhere in this world, rumoured to be impossible to trace now, a few prints survive of the original untouched film, with all its final bleakness intact.  Occasionally, videotapes and DVDs of this original film surface, copied from copies of copies.  Those who have seen these nth-generation copies say that despite the fuzziness and the bad sound, the Thakur's hopeless weeping is chilling, and it becomes clear to the viewer that all the visceral attractions of power and violence lead inevitably to this agony, this loss.

I wondered: had ALL copies disappeared?  Why hadn't the Sippys kept a few prints?  What was wrong with people?

But a few Youtube searches helped.  Here, then, are the original excised scenes, the ending and Ahmed's killing, which was also cut (not by the censors but by Sippy himself).