of the machine. The mechanic who has constructed the machine, however,
is permitted to keep the machine in running order, and if he suspects that
the machine has been operating incorrectly may put it back to one of its
previous positions and ask the schoolmaster to repeat his lessons from that
point on, but he may not take any part in the teaching. Since this proce-
dure would only serve to test the bona fides of the mechanic, I need hardly
say that it would not be adopted in the experimental stages. As I see it,
this education process would in practice be an essential to the production
of a reasonably intelligent machine within a reasonably short space of time.
The human analogy alone suggests this.
I may now give some indication of the way in which such a machine
might be expected to function. The machine would incorporate a memory.
This does not need very much explanation. It would simply be a list of all
the statements that had been made to it or by it, and all the moves it had
made and the cards it had played in its games. These would be listed in
chronological order. Besides this straightforward memory there would be a
number of 'indexes of experiences'. To explain this idea I will suggest the
form which one such index might possibly take. It might be an alphabetical
index of the words that had been used giving the 'times' at which they had
been used, so that they could be looked up in the memory. Another such
index might contain patterns of men or parts of a GO board that had
occurred. At comparatively late stages of education the memory might be
extended to include important parts of the configuration of the machine
at each moment, or in other words it would begin to remember what its
thoughts had been. This would give rise to fruitful new forms of indexing.
New forms of index might be introduced on account of special features
observed in the indexes already used. The indexes would be used in this sort
Whenever a choice has to be made as to what to do next features of
the present situation are looked up in the indexes available, and the previous
choice in the similar situations, and the outcome, good or bad, is discovered.
The new choice is made accordingly. This raises a number of problems. If
some of the indications are favourable and some are unfavourable what
is one to do? The answer to this will probably differ from machine to
machine and will also vary with its degree of education. At first probably
some quite crude rule will suffice, e.g., to do whichever has the greatest
number of votes in its favour. At a very late stage of education the whole
question of procedure in such cases will probably have been investigated by
by means of some kind of index, and this may result in
some highly sophisticated, and, one hopes, highly satisfactory, form of rule.
It seems probable however that the comparatively crude forms of rule will
themselves be reasonably satisfactory, so that progress can on the whole
be made in spite of the crudeness of the choice rules. This seems to be
verified by the fact that Engineering problems are sometimes solved by the
at SUB Bremen on June 20, 2012http://philmat.oxfordjournals.org/Downloaded from