Definition of Logos
In the first scene of the play, Bassanio asks Antonio for a loan so that he can travel to Belmont and woo Portia. Bassanio already owes Antonio money, but he offers an analogy to convince Antonio to give him the loan (even though Antonio has already offered to help his friend):
In my school-days, when I had lost one shaft,
I shot his fellow of the selfsame flight
The selfsame way, with more advised watch,
To find the other forth; and by adventuring both,
I oft found both.
Portia's suitors use logos as they attempt to deduce which casket holds her portrait—and while they all make convincing cases, each of their arguments proves troublesome.
Unlock with LitCharts A+In court, the Duke asks Shylock how he can expect to be treated mercifully if he doesn't exhibit any mercy. Shylock responds with a speech using logos:
Unlock with LitCharts A+You have among you many a purchased slave,
Which, like your asses and your dogs and mules,
You use in abject and in slavish parts
Because you bought them. Shall I say to you
"Let them be free! Marry them to your heirs!"
[...] You will answer
"The slaves are ours!" So do I answer you:
The pound of flesh which I demand of him
Is dearly bought; ’tis mine and I will have it.
If you deny me, fie upon your law.
In court, the law seems to be on Shylock's side. But as he is about to cut into Antonio and collect his bond, Portia (disguised as the lawyer Balthazar) tells him,
Unlock with LitCharts A+The words expressly are "a pound of flesh."
Take then thy bond, take thou thy pound of flesh,
But in the cutting it, if thou dost shed
One drop of Christian blood, thy lands and goods
Are by the laws of Venice confiscate / Unto the state of Venice.