Bava Mezia 46 and 47 Kidushin 28 The basic differences between Rashi , Tosphot, and the Rambam concerning exchange. To Rashi, there are only two categories: vessels or movable objects. There is no separate category of fruit. Thus, to Rav Nachman only vessels can cause acquisition by exchange or be acquired by exchange. To Rav Sheshet all movables can cause exchange, and be acquired by exchange. To Tosphot there are three categories: vessels, movables, and fruit. Vessels can cause exchange and be acquired by exchange. Movables can be acquired by exchange, but not cause exchange. (This is similar to how Rav Shach explains the Ravad) He holds that in exchange, neither object causes the acquisition. Rather, when one person picks up his object, then that is his.) When the other picks up his object, then that is his. To Tosphot fruit cannot be acquired nor cause acquisition by exchange, however when they are exchanged equal for equal, then they can be acquired by exchange and cause exchange [Tosphot Bava Mezia 47]. This is all very different from the Rambam who hold there a re two kinds of exchange: equal for equal, or handkerchief. To the Rambam even fruit can be acquired by exchange. All movables can cause exchange when exchanged for other movables. But vessels alone can be used as acquisition by means of a handkerchief.​-------------------------------------------------------------------Bava Mezia 46 and 47 Kidushin 28 The basic differences between Rashi , Tosphot, and the Rambam concerning exchange. To Rashi, there are only two categories: vessels or movable objects. There is no separate category of fruit. Thus, to Rav Nachman only vessels can cause acquisition by exchange or be acquired by exchange. To Rav Sheshet all movables can cause exchange, and be acquired by exchange. To Tosphot there are three categories: vessels, movables, and fruit. Vessels can cause exchange and be acquired by exchange. Movables can be acquired by exchange, but not cause exchange. (This is similar to how Rav Shach explains the Ravad) He holds that in exchange, neither object causes the acquisition. Rather, when one person picks up his object, then that is his.) When the other picks up his object, then that is his. To Tosphot fruit cannot be acquired nor cause acquisition by exchange, however when they are exchanged equal for equal, then they can be acquired by exchange and cause exchange [Tosphot Bava Mezia 47]. This is all very different from the Rambam who hold there are two kinds of exchange: equal for equal, or handkerchief. To the Rambam even fruit can be acquired by exchange. All movables can cause exchange when exchanged for other movables. But vessels alone can be used as acquisition by means of a handkerchief.

בבא מציעא דף מ''ו ע''ב. תוספות - המילים הראשונות ולרב נחמן". בקיצור, רבינו תם קובע כי פירות שווים גורמים או נרכשים על ידי חליפין. תוספות שואלים על כך מן הגמרא. הגמרא אומרת שאם מטבע יכול לשמש להחלפה, וזו תהיה כוונת המשנה "כל מה שנעשה כסף עבור אחר", ברגע שאחד רוכש, גם השני רוכש. אז למה יכול להתייחס סוף המשנה, המתייחס להחלפה של שתי חיות? אחרי הכל, אין כאן מטבע. הגמרא עונה שסוף המשנה ואומרת לנו שניתן להשתמש בפירות כהחלפה. הגמרא שואלת על כך והלא רב נחמן מחזיק בפירות, שלא ניתן להשתמש בהם להחלפה. התשובה של תוספות יכולה להיות שהמשנה מתייחסת למקרה של שווה תחת שווה. תוספות עונה שהמשנה אינה מתייחסת למקרה של שווה תחת שווה. אבל תוספות מרחיק לכת ואומר שאפילו בדרך שבה רב יהודה מבין את המשנה, זה גם לא מתייחס לשווה בשביל שווה. אבל השאלה על זה היא למה בכלל להזכיר את רב יהודה? למה זה יהיה נחוץ בכלל? הרי השאלה הייתה רק על רב נחמן. הסתפקנו בתשובת רב יהודה הייתי בים ועלה בדעתי מדוע תוספות מעלה את הרעיון שאפילו אם נלמד את המשנה כ"כל הנישום", זה עדיין לא שווה תמורת שווה. אני חושב שהסיבה היא שאם חליפין עובד בעבור תמורת פירות כאשר הערך הכספי של כל אחד שווה תמורת שווה, אז אפילו רב יהודה לא היה צריך לבוא על התשובה "כל הנישום". הוא היה יכול לומר ש"כל הנעשה" יכול להתייחס לפירות ולכל החפצים הנעים כאשר זה שווה תמורת שווה. עם זאת, אני חייב לציין שיש ויכוח בין המהרש"א למהר"ם שיף לגבי מה התכוונו תוספות לומר כשהוא מעלה את תשובתו של רב יהודה. שתי התשובות נראות לי סבירות, אולם אני חושב שהתשובה שלי היא פשוטה יותר. כלומר, אם רבינו תם היה צודק והמשנה הייתה יכולה להיות שווה תחת שווה, אז רב יהודה לא היה צריך להגיע לתשובה קשה לגבי המשנה כאשר תשובה פשוטה יותר הייתה זמינה

Bava Mezia page 46b. Tosphot first words and to Rav Nachman”. In short, Rabainu Tam holds equal for equal works to cause or to be acquired by exchange even for fruit. Tosphot asks on this from the Gemara. The Gemara says if coin can be used for exchange, and that would be the intension of the Mishna “all that is made money for another”, once one acquires, the other also acquires. Then what could the end of the Mishna which refers to exchange of two animals be referring to. After tall, there is no coin here. The gemara aanswers the end of the Mishna tell us fruit can be used in exchange. The Gemara asks on this from Rav Nachman who holds fruit cannot be used for exchange. The answer could be that the Mishna is referring to a case of equal for equal. Tosphot answers the Mishna is not refering to a case of equal for equal. But Tosphot goes further and says even in the way Rav Judah understands the Mishna, it is also not referring to equal for equal. But the question on this is why mention Rav Judah at all? Why would this be necessary at all? After all the question was only on Rav Nachman. We were satisfied with the answer of Rav Judah. I was at the sea and it occurred to me why tosphot brings up the idea that even if we learn the Mishna as "all that is evaluated" it still is not equal for equal. I think the reason is that if exchange works for fruit when the monetary worth of each is equal for equal then even rav judah would not have had to come onto the answer for "all that is evaluated". He could have said all that is made could refer to fruit and all movable objects when it is equal for equal. however, I must mention that there is an argument between the Maharsha and the Maharam Shif about what Tosphot means to say by bring up the answer of Rav Judah. Both answers seem reasonable to me however I think my answer is simpler. that is if Rabainu Tam would be right then Rav Judah would not have had to come onto difficult answer about the mishna when a simpler one was available.-----------------------------------------------------------------------------בבא מציעא page מ''ו ע''ב. תוספותfirst words and to רב נחמן”. I was at the sea and it occurred to me why תוספותbrings up the idea that even if we learn the משנה as "כל הנישום" it still is not equal for equal. I think the reason is that if exchange works for fruit when the monetary worth of each is equal for equalת then even רב יהודהwould not have had to come onto the answer כל הנישום . He could have said "כל הנעשה" could refer to fruit and all movable objects when it is equal for equal. However, I must mention that there is an argument between the מהרש''א and the מהר''ם שיף about what תוספות means to say by bring up the answer of רב יהודה. Both answers seem reasonable to me, however I think my answer is simpler. That is, if רבינו תם would be right and the משנה could be a case of equal for equal, then רב יהודה would not have had to come onto difficult answer about the משנה when a simpler one was available. in short rabainu tam holds qequal for equal works to cause or to be acquired by exchange even for fruit. tosphot asks on this from the gemara. the gemara says if coin can be used for exchange and that would be the intension of the mishna all that is made monney for another, once one acquires the other also acquires. then what could the end of the mishna which refers to exchange of two anumals be refering to. after tall, there is no coin here. answer the end tell us fruit can be used in exchange. the gemara asks ogfn this from rav nachma who holds friuit canot be used for exchange. the answer could be that the mishna is refering to a case of equal for equal. tosphot answrs the mishna is not refer to a case of equal for equal. but tosphot goes further and says even in the way rav juda understands the mishna, it is also not refering to equal for equal. why would this be neccessary at all? after all the question was only on rav nachman. we were satisfied with the answer of rav juday.----------------- In short, רבינו תם holds equal for equal works to cause or to be acquired by exchange even for fruit. תוספותasks on this from the גמרא. The גמרא says if coin can be used for exchange, and that would be the intension of the משנה “all that is made money for another”, once one acquires, the other also acquires. Then what could the end of the משנה which refers to exchange of two animals be referring to. After tall, there is no coin here. The גמרא answers the end of the משנה tell us fruit can be used in exchange. The גמרא asks on this from רב נחמן who holds fruit cannot be used for exchange. The answer could be that the משנה is referring to a case of equal for equal. תוספות answers the משנה is not referring to a case of equal for equal. But תוספות goes further and says even in the way רב יהודה understands the משנה , it is also not referring to equal for equal. But the question on this is why mention רב יהודה at all? Why would this be necessary at all? After all the question was only on רב נחמן. We were satisfied with the answer of רב יהודה.

ברמב"ם הלכות מכירה פרק ה' הוא מביא את חוק החליפין. אבל במקרה של רכישה בכסף בפרק א' הוא לא מביא את חוק החליפין. נראה מכך שהחלפת חפצים אינה רכישה בכסף. למרות שמה שיש לו ערך כספי נחשב לפעמים ככסף, עדיין ישנם מקרים שבהם זה לא כך, למשל פדיון עבד עברי צריך להיות באמצעות כסף, לא מה ששווה כסף. דוגמאות נוספות הן בדיני גניבה שבהן יש ויכוח האם אפשר לשלם במה שיש לו ערך כספי. לכן, כאשר הגמרא אומרת שאי אפשר לשאת אישה בהחלפה, פירוש הדבר החלפה בכלים כמו מטפחת, לא החלפה שווה תחת שווה. כאן אני רק מזכיר בקצרה את מה שאומר רב שך בתחילת חוקי אישות

In the Rambam laws of sale chapter 5 he brings the law of exchange. but in the case of acquisition by money in chapter 1 he does not bring the law of exchange. It seems clear from this that exchange of objects is not acquisition by money. Even though that which has monetary value is sometimes considered to be like money, still there are cases where it is not, for example the redemption of a Jewish slave has to be through money, not that which is worth money. Other examples are in laws of theft where there is an argument if one can pay by that which has monetary value. So when the Gemara says one cannot marry a wife by exchange that means exchange by vessels like a handkerchief, not exchange equal for equal. Here I am just mentioning in short what Rav Shach says in the beginning of laws of marriage.------------------------------------------------------------------------------------------------------------------- In the רמב''ם הלכות מכירה פרק ה' 5 he brings the law of exchange. But in the case of acquisition by money in chapter א' he does not bring the law of exchange. It seems clear from this that exchange of objects is not acquisition by money. Even though that which has monetary value is sometimes considered to be like money, still there are cases where it is not, for example the redemption of a Jewish slave has to be through money, not that which is worth money. Other examples are in laws of theft where there is an argument if one can pay by that which has monetary value. So when the גמרא says one cannot marry a wife by exchange that means exchange by vessels like a handkerchief, not exchange equal for equal. Here I am just mentioning in short what רב שך says in the beginning of laws of marriage.

בבא מציעא דף מ''ו ע''א וע''ב. המשנה אומרת, "כל מה שנעשה ערך כספי באחר, ברגע שאחד רוכש אותו, השני רוכש את החליפו. כיצד זה? אם אדם מחליף שור בפרה, ברגע שאחד רוכש אחד, השני רוכש את השני." הגמרא שואלת שנראה שהמשנה מתכוונת שמטבע יכול לגרום להחלפה, (ואנחנו יודעים שזה לא המצב). אז רב יהודה אומר שזה אומר שאם אדם מעריך חפץ ברגע שהוא רוכש את הראשון, השני רוכש את השני. [כלומר, החלפה זו צריכה הערכה.] הגמרא שואלת בנקודה זו שה"הייתי חושב" היה נכון לפחות לפי לוי שחליפת מטבע יכולה לגרום לקניין. אז איך הבינה הגמרא את המשנה בנקודה זו? אחרי הכל, לדוגמה שהיא נותנת אין לה שום רלוונטיות למטבעות. (הדוגמה היא פרה תמורת שור.) תשובה. המשנה פירושה שמטבעות יכולים לגרום להחלפה, וגם פירות. (הדוגמה של שור לפרה היא דוגמה לפרי.) אבל עבור רב נחמן שמחזיק פירות לא יכולים לגרום להחלפה, מה יכולה להיות הכוונה? כאן תוספות שואל על רבינו תם שאולי המשנה קידושין דף כ"ח מדברת על החלפה שווה תחת שווה, ובמקרה כזה פירות יכולים לגרום להחלפה לפי רבינו תם. הוא עונה שזה לא יכול להיות כך, מכיוון שסוף המשנה צריך להיות כמו ההתחלה, וההתחלה בבירור אינה שווה תחת שווה. אני לא מבין מדוע זה כך. לפי הייתי חושב (הוה אמינא) אנחנו מדברים על החוק שניתן להחליף מטבע. "כל מה שהופך לערך כסף עבור משהו אחר, ברגע שאחד רוכש את החפץ, השני רוכש את החפץ המוחלף." היכן אנו רואים כאן שלא מדובר על שווה תמורת שווה?תשובה אפשרית לשאלה זו של תוספות על רב נחמן היא שאולי רב יהודה אומר שהחליפין צריך להיות שווה עבור שווה, (שכן אחרת למה צריך להעריך את השווי הכספי של כל חפץ?) ולכן גישתו של רב נחמן שונה והוא חייב להחזיק "כל הנעשה דמים נאחר" פירושו כלים שאינם שווים עבור שווים. עם זאת, ברור שתוספות לא עונה כך. הוא גורס שאפילו דעתו של רב יהודה, שכאשר הוא אומר "כל הנישום דמים באחר", משתמע מכך שהם אינם שווים בערכם

Bava Mezia page 46 side a and b. The Mishna says, “All that is made monetary value in another, once one acquires it, the other acquires its exchange. How is this. if one exchanges an ox for a cow, once one acquires one, the other acquires the other.” The gemara asks that it seems the Mishna means that a coin can cause exchange, (and we know that is not the case). So Rav Juda says it means if one evaluates an object once one acquires the first the other acquires tthe second. [ie that exchange needs evaluation.] the gemara asks at this point that the hava amina (I would have thought) was at least true according to Levi or Rav that holds a coin can cause exchange. So how did the Gemara understand the Mishna at that point? After all, the example it gives has no relevance to coins. (The example is a cow and for an ox) Answer. The mishna means coins can cause exchange, and fruit also. (The example of a ox for a cow is an example of fruit.) But to Rav Nachman who holds fruit can not cause exchange, what could the Mishna mean? Here Tosphot asks on Rabainu Tam that perhaps the Mishna in Kidushin page 28 is talking about exchange equal for equal, and in that case fruit can cause exchange according to Rabbainu Tam. He answers that that can not be so, since the end of the mishna has to be like the beginning, and the beginning is clearly not equal for equal. I fail to see why this is so. according to the I would have thought (hava amina) we arre talking about the law that a coin can be exchanged. ''All that is made money value for something else, once one acquires the object, the other acquires the exchanged object. '' Where do we see here that it is not talking about equal for equal? A possible answer to this question of Tosphot on Rav Nachman is that perhaps Rav Judah means that the exchange has to be equal for equal, (since otherwise why would one have to evaluate the monetary worth of each object?) and therefore approach of Rav Nachman is different and he must hold “All that is made monetary value in other” means vessels that are not equal for equal. However, it is clear that Tosphot does not answer this. He holds that even the opinion of Rav Judah is that when he says one must evaluate the worth of each object, that implies they are not equal in value. -------------------------------------------------------------------------------------------------------------------------------------- ---- בבא מציעא page מ''ו ע''א וע''ב. The משנה says, “All that is made monetary value in another, once one acquires it, the other acquires its exchange. How is this. if one exchanges an ox for a cow, once one acquires one, the other acquires the other.” The גמרא asks that it seems the משנה means that a coin can cause exchange, (and we know that is not the case). So רב יהודה says it means if one evaluates an object once one acquires the first, the other acquires the second. [ie that exchange needs evaluation.] The גמרא asks at this point that the הווה אמינא (I would have thought) was at least true according to לוי (or Rav) that holds a coin can cause exchange. So how did the גמרא understand the משנה at that point? After all, the example it gives has no relevance to coins. (The example is a cow and for an ox) Answer. The משנה means coins can cause exchange, and fruit also. (The example of a ox for a cow is an example of fruit.) But to רב נחמןwho holds fruit can not cause exchange, what could the משנה mean? Here תוספות asks on רבינו תםthat perhaps the משנה in קידושין page כ''ח is talking about exchange equal for equal, and in that case fruit can cause exchange according to רבינו תם . He answers that that can not be so, since the end of the משנה has to be like the beginning, and the beginning is clearly not equal for equal. I fail to see why this is so. according to the I would have thought (הווה אמינא) we are talking about the law that a coin can be exchanged. ''All that is made money value for something else, once one acquires the object, the other acquires the exchanged object. '' Where do we see here that it is not talking about equal for equal? A possible answer to this question of תוספות on רב נחמן is that perhaps רב יהודה means that the exchange has to be equal for equal, (since otherwise why would one have to evaluate the monetary worth of each object?) and therefore approach of רב נחמןis different and he must hold “כל הנעשה דמים נאחר” means vessels that are not equal for equal. However, it is clear that תוספות does not answer this. He holds that even the opinion of רב יהודהis that when he says "כל הנישום דמים באחר", that implies they are not equal in value.