CHAPTER I.
Love, according to the unanimous opinion of the wise men who discourse of him, and as by experience we see continually, is that which brings together and unites the lover with the beloved; wherefore Pythagoras says, "In friendship many become one." And the things which are united naturally communicate their qualities to each other, insomuch that sometimes it happens that one is wholly changed into the nature of the other, the result being that the passions of the beloved person enter into the person of the lover, so that the love of the one is communicated to the other, and so likewise hatred, desire, and every other passion; wherefore the friends of the one are beloved by the other, and the enemies hated; and so in the Greek proverb it is said: "With friends all things ought to be in common." Wherefore I, having made a friend of this Lady, mentioned above in the truthful exposition, began to love and to hate according to her love and her hatred.

I then began to love the followers of Truth, and to hate the followers of Error and Falsehood, even as she does.

But since each thing is to be loved for itself and none are to be hated except for excess of evil, it is reasonable and upright to hate not the things, but the evil in the things, and to endeavour to distinguish between these.

And if any person has this intention, my most excellent Lady understands especially how to distinguish the evil in anything, which is the cause of hate; since in her is all Reason, and in her is the fountain-head of all uprightness.
I, following her as much as I could in her work as in her love, abominated and despised the errors of the people with infamy or reproach, not cast on those lost in error, but on the errors themselves; by blaming which, I thought to create displeasure and to separate the displeased ones from those faults in them which were hated by me.

Amongst which errors one especially I reproved, which, because it is hurtful and dangerous not only to those who remain in it, but also to others who reprove it, I separate it from them and condemn.
This is the error concerning Human Goodness, which, inasmuch as it is sown in us by Nature, ought to be termed Nobility; which error was so strongly entrenched by evil custom and by weak intellect that the opinion of almost all people was falsified or deceived by it; and from the false opinion sprang false judgments, and from false judgments sprang unjust reverence and unjust contempt; wherefore the good were held in vile disdain, and the evil were honoured and exalted.