J. B. Ss HALDANE 
it realize that a sudden turn through any angle in one of these 
planes was represented by a turn through the same angle in 
the other (or in mathematical language, that mapping was 
conformal) ? Ifso it would have the same sorts of intuition about 
functions of a complex variable as anyone who looks at their 
graphs has about those of a real variable. The truth or pos- 
sibly the falsehood of Riemann’s hypothesis about the Zeta 
function, which is the missing key to prime number theory, 
might be intuitively obvious, even if its formal proof were still 
difficult. 
And man would effectively have broken through into the 
fourth dimension. As the least unintelligible account of the 
fundamental properties of ordinary matter is in terms of func- 
tions of complex variables, and three-dimensional intuition is 
a poor guide to these properties on the subatomic scale, such a 
break-through would be of great practical value. If, say, it 
were found that one person in a thousand possessed this capa- 
city, they would have, like chess players and musicians, to 
develop their own vocabulary. This would probably revolu- 
tionize not only physical but biological theory. 
However, a more generalized conscious apprehension and 
control of our bodies would be of still greater importance. If 
one observes a yogi, one finds that he has developed the same 
kind of power over his trunk muscles as a skilled craftsman or 
sportsman has over his limb muscles. Thus he can contract his 
right and left rectus abdominis independently, as a pianist can 
move his fingers independently. This control extends to a less 
extent to the heart and smooth muscles. Thus yogis can slow 
their hearts down, though it is doubtful whether they can stop 
them. They describe qualitatively new bodily sensations, such 
as that of kundalini. Their verbal accounts of these activities 
often appear to be nonsense; but no form of words which leads 
to concerted human activity is nonsense. It may be a pity that 
musicians use the word coloratura and algebraists the word 
‘spur’? with esoteric meanings. The yogis are perhaps a bit 
worse, but not much. In particular, I suspect that they have 
been grossly mistranslated. The human nervous system is said 
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