THE BELFAST ADD&ES& 455 
exist, and showed on general principles why animals must 
have such and such parts. When an eminent contemporary 
philosopher, who is far removed from errors of this kind, 
remembers these abuses of the a jtriori method, lie will be 
able to make allowance for the jealousy of physicists as to 
the acceptance of so-called a priori truths. Aristotle's 
errors of detail, as shown by Eucken and Lange, were grave 
and numerous. He affirmed that only in man we had the 
beating of the heart, that the left side of the body was 
colder than the right, that men have more teeth than 
women, and that there is an empty space at the back of 
e v ery maji!s Ji ead . 
There is one essential quality in physical conceptions, 
which was entirely wanting in those of Aristotle and his 
followers a capability of being placed as coherent pictures 
before the mind. The Germans express the act of picturing 
by the word vorstellen, and the picture they call a Vorstel- 
lung. We have no word in English which comes nearerlo 
our requirements than Imagination; and, taken with its 
proper limitations, the word answers very well. But it is 
tainted by its associations, and therefore objectionable to 
some minds. Compare, with reference to this capacity of 
mental presentation, the case of the Aristotelian, who 
refers the ascent of water in a pump to Nature's abhorrence 
of a vacuum, with that of Pascal when he proposed to solve 
the question of atmospheric^ pressu re by the ascent of the 
Puy de Dome. In the one case the terms of the explanation 
refuse to fall into place as a physical image; in the other the 
image is distinct, the descent and rise of the barometer 
being clearly figured beforehand as the balancing of two 
varying and opposing pressures. 
SECTION 3. During the drought of the middle ages in 
Christendom, the Arabian intellect, as forcibly shown by 
Draper, was active. With the intrusion of the Moors into 
Spain, order, learning and refinement took the place of 
their opposites. When smitten with disease, the Christian 
peasant resorted to a shrine, the Moorish one to an 
instructed physician. The Arabs encouraged translations 
from the Greek philosophers, but not from the Greek 
poets. They turned in disgust "from the lewdness of our 
classical mythology, and denounced as an unpardonable 
blasphemy all connection between the impure Olympian 
