The Promise of Medical Science* 
ALBERT SZENT-GYORGYI 
point which divides the past from the future. If we want to 
look into the future, we can do this only by studying the past 
and then extrapolating. The history of science is built of three 
periods: the science of antiquity, classical science, and modern 
science. 
What characterized the science of antiquity, represented by 
the natural philosophy of Aristotle, the geometry of Euclid and 
the cosmology of Ptolemy, was the absolute faith in the senses 
and reasoning of man. There was no doubt in the minds of these 
philosophers that the world was really as they saw it, and that 
what they saw was the ultimate reality. Problems beyond their 
reach could be answered by a process of reasoning that was as 
infallible as their senses. The earth was flat, there was an 
“up” and ‘“‘down”’,and around this earth revolved the sun and 
skies, 
That great awakening of the western human mind, the 
Renaissance, gave rise to a new science. This was characterized 
by a more modest and humble attitude which recognized that 
neither our senses nor our reasoning are perfect. To have a 
better understanding of the world we have to improve our senses 
with instruments and support our reasoning with careful obser- 
vation, measurement, experimentation and calculation. This 
new science, which is often called ‘“‘classical’’, and which 
culminated in the work of Newton, corrected many earlier 
errors and extended man’s world, but introduced nothing that 
man could not “understand’’, that is, correlate with some 
[: we symbolize human history by a line, the present is only a 
* Author was supported by a grant from the National Institutes of Health (No. 
GM-10383), and a grant from the National Science Foundation (No. G-5836). 
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