The world is not a factory and animals are not products for our use

Men best show their character in trifles, where they are not on their guard. It is in the simplest habits, that we often see the boundless egotism which pays no regard to the feelings of others and denies nothing to itself.

Philosophy ... is a science, and as such has no articles of faith; accordingly, in it nothing can be assumed as existing except what is either positively given empirically, or demonstrated through indubitable conclusions.

For our improvement we need a mirror.

Ordinary people merely think how they shall 'spend' their time; a man of talent tries to 'use' it.

The vanity of existence is revealed in the whole form existence assumes: in the infiniteness of time and space contrasted with the finiteness of the individual in both; in the fleeting present as the sole form in which actuality exists; in the contingency and relativity of all things; in continual becoming without being; in continual desire without satisfaction; in the continual frustration of striving of which life consists. . . Time is that by virtue of which everything becomes nothingness in our hands and loses all real value.

Every generation, no matter how paltry its character, thinks itself much wiser than the one immediately preceding it, let alone those that are more remote.