Baba Basra 174a - More about Areiv and Kablan

In the post yesterday I pointed to a machlokes between the ketzos and nesivos whether the obligation of an areiv is a result of the pleasure he receives by the lender willing to lend based on his acceptance of responsibility, or whether we view the lender to be serving as an agent of the areiv in the lending of the money.

It seems that this is actually the difference between an areiv and a kablan. The gemara 174a points out that language of "give" is indicative of kablan, whereas language of "lend" is indicative of an areiv. The Rashbam explains - תן לו: מסור הממון בידו ואני אפרענו לך, אין כאן לשון הלואה אלא שליחותיה דהאי דקאמר "תן לו" עביד מלוה. The Rashbam seems to understand that the shi'bud of a kablan is a result of shlichus (like the ketzos). Meaning, the the lender is serving as the agent of the kablan by lending the money, so that the lender can surely go to the person who commanded him and sent him, which is the kablan, to collect. Basically, in the set up of a kablan, the relationship seems to be between the kablan and the lender, where the lender serves as the shliach of the kablan in the loan. But, in the set up of an areiv the relationship is between the borrower and the areiv, where the areiv accepts the responsibility to cosign for him. Therefore, the shi'bud of the areiv is a result of the benefit that he gets as the gemara explains, not the lender serving as his shliach.

With this we can understand the gemara 173b that originally brought a proof to the shi'bud of an areiv from the pasuk by Yehuda, and then says that it wasn't a situation of areiv, rather a situation of kablan. The gemara means to say that Yehuda's relationship is with yakov, yehuda is the kablan and yakov is the giver (or lender), therefore it is more similar to kablan than to areiv. The gemara seems to hold that a kablan is not just a stronger areiv, because if that were the case then the ability to prove that kablanus works would imply that areiv certainly works, so what is the dichuy? The gemara seems to understand that the mechanics of how an areiv is obligated is completely different from the mechanics in how a kablan is obligated, that is why a kablan isn't a proof for an areiv. Basically, an areiv is bound as explained by the nesivos, whereas a kablan is bound as explained by the ketzos.