DISCUSSION 
Finally, Gédel’s theorem is not applicable to any machine 
complex enough to contain a random element of correction. 
Gédel’s theorem applies only to purely deductive systems. Any 
machine more interesting than a thermostat, any machine with 
an exploratory part, or which can change its wiring at random 
—to any such machine, none of these restrictions apply. For 
goodness sake don’t let us be frightened of the Almighty in the 
shape of a thermostat! 
MacKay: My point, which I think Dr. Bronowski has 
missed, was indeed that society is not of such a kind that it can 
be given infallible predictions about its own activity. If the 
social unit whose behaviour is being predicted were to equip 
itself with an identical computer, for example, it could certainly 
be able, as Dr. Bronowski points out, to thumb its nose at the 
person who is trying to do the predicting. 
The feedback scheme that I described (of which the thermo- 
stat is the zero-order example) is only the basic diagram for any 
kind of adaptive government or control. ‘There is no doubt at 
all that if such a predictive model is being used and if the 
members of the society are unaware of this, then, as Dr. Bronow- 
ski must realize, they are much more vulnerable to manipula- 
tion than they might have supposed. It is certainly true, as my 
paper pointed out, that the more people were aware what 
the government or others were doing with computing appar- 
atus, the less passive would they be in the hands of the manipu- 
lators. 
As for his reference to Gédel’s theorem, no randomizing 
element can remove the restriction we were discussing, which 
was precisely on our power to deduce that a specification of 
ourselves was adequate. I can assure Dr. Bronowski that a 
randomized machine would have a harder, not an easier, job to 
arrive at an exhaustive self-description. 
Lipmann: I wonder if Bronowski is not being too optimistic 
in his trust that evolution is self-regulating. We are at a point of 
evolution where we have to be extremely careful, because we 
are moving into an entirely different and more precarious 
phase. There are societies in nature that have become fossilized 
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