An emotion is stronger in proportion to the number of simultaneous concurrent causes whereby it is aroused.
Proof .-- Many simultaneous causes are more powerful than a few (III.

vii.): therefore (IV.

v.), in proportion to the increased number of simultaneous causes whereby it is aroused, an emotion becomes stronger.

Q.E.D.
Note--This proposition is also evident from V.Ax.

ii.
PROP.IX.