Over the holidays I began to study chess. It’s something I’ve wanted to do all my life but had no idea how to go about learning the game. Then I discovered an iPhone chess app called iChess. In addition to the free game, iChess Lite, the author, Tom Kerrigan, provides a free ebook titled “Learn Chess.” Then before Christmas I bought the full-blown iChess Pro app—and now I’m hooked.

It didn’t take long for me to realize that a chess game is a bit like a criminal trial: everyone expects the “best” side to win. But the contest is actually so complex that the outcome is never certain. Each side can anticipate the opponent’s moves only to a certain extent. There’s rarely only one “correct” move to make at any given time.

When I realized this about chess, I concluded that psychology has more to do with winning than most people think. That’s why (IMHO) a great chess player ought to be able to beat Big Blue every time. Human beings take risks sometimes and even sacrifice pawns and powerful pieces to set a trap.

I suspect that most jurors take their seats in the jury box assuming that the best side will win, that the moves are finite, though intricate, and that at each step in the trial there is a prescribed move for each side to make.

The rules of a trial reinforce that idea: voir dire comes first, the judge instructs the jury and reads the indictment, the prosecution delivers an opening statement, the defense delivers an opening statement, the prosecution presents its case, the defense presents its case, the prosecution presents a summation, the defense presents its closing argument, the prosecution presents its closing argument, the judge reads the jury instructions and verdict form, and the jury deliberates.

A trial’s rhetorical structure derives not only from common law tradition but also classical rhetoric (as ancient as the Greeks). It’s a structure that supposedly puts the burden of proof on the “pro” side of the argument. In a trial the prosecution is the pro side: its proposition is that the defendant is guilty of a crime.

Having assumed the burden of proof, the pro side is given the last word—a closing argument that is intended to “ring in the jurors' ears,” to resonate throughout the deliberations so that the side with the greatest burden is given a bit of a break and by the end all things should be equal.

Chess is like that, too. It begins with white’s move, but black is not only permitted, it is required, to respond immediately. The rules of the game are intended to keep all things equal for as long as possible until a clear winner emerges.

The problem is that in both chess and criminal trials modern technology has intervened. In chess, supercomputers are now programmed to calculate all the possible moves, permutations and combinations of moves, and all possible outcomes. An objective observer of a game (a juror) between a human and a machine anticipates the machine will win. Watching a chess match between a human player and a computer is a very different experience from watching a match between two people.

Jurors who observe a criminal trial anticipate that the prosecution will win if it brings technology into the courtroom. The mere mention of DNA implies certainty as to the identity of the criminal. There can be no reasonable doubt in such a case.

The burden of proof has shifted from the prosecution to the defense. But the rules of the game have not changed in 2500 years. The prosecution still always gets to move first and last.

(I have some thoughts on how the defense can regain parity, but I will save that for another post.)