aterial of his ordinary reasoning, are here
banished on the ground that they are 'not evidence,' and witnesses are
compelled to give a simple account of their remembered sensations of
sight and hearing.

The witnesses for the prosecution and the defence, if they are
well-intentioned men, often find themselves giving, to their own
surprise, perfectly consistent accounts of the events at issue. The
barristers' tricks of advocacy are to some extent restrained by
professional custom and by the authority of the judge, and they are
careful to point out to the jury each other's fallacies. Newspapers do
not reach the jury box, and in any case are prevented by the law as to
contempt of court from commenting on a case which is under trial. The
judge sums up, carefully describing the conditions of valid inference on
questions of disputed fact, and warning the jury against those forms of
irrational and unconscious inference to which experience has shown them
to be most liable. They then retire, all carrying in their minds the
same body of simplified and dissected evidence, and all having been
urged with every circumstance of solemnity to form their conclusions by
the same mental process. It constantly happens therefore that twelve
men, selected by lot, will come to a unanimous verdict as to a question
on which in the outside world they would have been hopelessly divided,
and that that verdict, which may depend upon questions of fact so
difficult as to leave the practised intellect of the judge undecided,
will very generally be right. An English law court is indeed during a
well-governed jury trial a laboratory in which psychological rules of
valid reasoning are illustrated by experiment; and when, as threatens to
occur in some American States and cities, it becomes impossible to
enforce those rules, the jury system itself breaks down.[73]

[73] On the jury system see Mr. Wells's _Mankind in the Making_, chapter
vii. He suggests the use of juries in many administrative cases where it
is desirable that government should be supported by popular consent.

At the same time, trial by jury is now used with a certain degree of
economy, both because it is slow and expensive, and because men do not
make good jurors if they are called upon too often. In order that
popular consent may support criminal justice, and that the law may not
be unfairly used to protect the interests or policy of a governing class
or person, no man, in most civilise