Full Idea
If the citizen is deterred from seeking his personal welfare in any way he chooses which is consistent with the freedom of others, the vitality of business in general and hence also the strength of the whole are held in check.
Gist of Idea
The vitality of business needs maximum freedom (while avoiding harm to others)
Source
Immanuel Kant (Idea for a Universal History [1784], 8th)
Book Reference
Kant,Immanuel: 'Political Writings', ed/tr. Reiss,Hans [CUP 1996], p.50
A Reaction
This is a rather American view of liberalism. Kant has been praising the virtues of aggressive competition.