...it's true; but what kind of a long novel would it be if thehero had no incentive... 
Various 「Astounding Stories, August, 1931」
...It is one of the damning characteristics of the slave system, that it robs its victims of every earthly incentive to a holy life...
Frederick Douglass 「My Bondage and My Freedom」
... And how is he to do itwith ten, fifteen, or twenty years' imprisonment before him? Thehope of liberty and of opportunity is the only incentive to life,especially the prisoner's life...
Emma Goldman 「Anarchism and Other Essays」
...Such an arrangement serves to givethe incubator man a greater incentive to give themachines good attention and to secure just the bestresults of which he is capable...
Harry M. Lamon 「Ducks and Geese」
...
Affection an incentive, ...
Dinks, Mayhew, and Hutchinson 「The Dog」
...Hugo set down my bag, accepted another gold coin; and with a queersidelong smile, the incentive for which I had not the slightest idea,he vanished...
Various 「Astounding Stories of Super-Science September 1930」
...This is a higher, nobler,and greater incentive to righteousness than any life of personal rewardor fear of punishment in a future life...
Dr. D.M. Brooks 「The Necessity of Atheism」
...Oppression gives a spring to the soul; it obliges man to examine closely into the cause of his sorrows; misfortune is a powerful incentive, that turns the mind to the side of truth...
Paul Henri Thiery (Baron D'Holbach) Samuel Wilkinson 「The System of Nature, Volume 2」
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