“Thoughts without content are empty, intuitions without concepts are blind.”

“Two things fill the mind with ever new and increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above me and the moral law within me. I do not seek or conjecture either of them as if they were veiled obscurities or extravagances beyond the horizon of my vision; I see them before me and connect them immediately with the consciousness of my existence.”

“Even if a civil society were to be dissolved by the consent of all its members (e.g., if a people inhabiting an island decided to separate and disperse throughout the world), the last murderer remaining in prison would first have to be executed, so that each has done to him what his deeds deserve and blood guilt does not cling to the people for not having insisted upon this punishment; for otherwise the people can be regarded as collaborators in his public violation of justice.”

“If man makes himself a worm he must not complain when he is trodden on.”

“The business of philosophy is not to give rules, but to analyze the private judgments of common reason.”

“Answer me, you who believe that animals are only machines. Has nature arranged for this animal to have all the machinery of feelings only in order for it not to have any at all?”

“There are barbarians who seize this dog, who so prodigiously surpasses man in friendship, and nail him down to a table, and dissect him alive to show you the mezaraic veins... Answer me, Machinist, has Nature really arranged all the springs of feeling in this animal to the end that he might not feel? Has he nerves that he may be incapable of suffering?”

“We should be able to refuse to live if the price of living be the torture of sentient beings.”