Wikipedia: "Symposium"
In ancient Greece, the symposium (Greek: συμπόσιον symposion or symposio, from συμπίνειν sympinein, "to drink together") was a part of a banquet that took place after the meal, when drinking for pleasure was accompanied by music, dancing, recitals, or conversation.
The Greek symposium was a key Hellenic social institution. It was a forum for men of respected families to debate, plot, boast, or simply to revel with others. They were frequently held to celebrate the introduction of young men into aristocratic society. Symposia were also held by aristocrats to celebrate other special occasions, such as victories in athletic and poetic contests. They were a source of pride for them.
Symposia were usually held in the andrōn (ἀνδρών), the men's quarters of the household. The participants, or "symposiasts", would recline on pillowed couches arrayed against the three walls of the room away from the door.
The men at the symposium would discuss a multitude of topics—often philosophical, such as love and the differences between genders.
A symposium would be overseen by a "symposiarch" who would decide how strong the wine for the evening would be, depending on whether serious discussions or merely sensual indulgence were in the offing. The Greeks and Romans customarily served their wine mixed with water, as the drinking of pure wine was considered a habit of uncivilized peoples.
וְאָמַר רַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי: נָשִׁים חַיָּיבוֹת בְּאַרְבָּעָה כּוֹסוֹת הַלָּלוּ, שֶׁאַף הֵן הָיוּ בְּאוֹתוֹ הַנֵּס.
And Rabbi Yehoshua ben Levi said: Women are obligated in these four cups of wine at the Passover seder. As they too were included in that miracle of the Exodus, they are therefore obligated to participate in the celebration.
יש מקשים, מה הועיל* לנו היציאה, הרי אנו משועבדים בשאר מלכיות, דמאי שנא מלכות מצרים משאר מלכיות. ודברי הבאי הם, כי כאשר יצאו ישראל ממצרים קבלו הטוב בעצם, עד שהיו ראוים בעצמם להיות בני חורין מצד מעלתם, וזאת המעלה עצמית לישראל, שהם ראוים להיות בני חורין מצד עצם מעלתם. ודבר מקרי לא יבטל דבר עצמי כלל, כי עדיין על ישראל המעלה הזאת, שהם בני חורין בעצם, עם השעבוד במקרה. כי אחר שהוציא הקב"ה את ישראל ממצרים, ונתן אותם בני חורין, ולא עוד אלא אף מלכים, שנאמר (שמות יט, ו) "ואתם תהיו לי ממלכת כהנים וגוי קדוש", זה השם הוא לישראל בעצם, והמעלה והחשיבות שיש בזה לא נתבטל בגלותם, שהוא במקרה. ולפיכך אומרים חכמי ישראל (שבת סז.) "כל ישראל בני מלכים הם" אף בגלותם, וזה מצד המעלה והחשיבות שקנו ישראל בעצם, לא נתבטל במקרה כלל. ואין ספק שכמה דברים הם נמשכים אל ישראל מן המעלה והחשיבות, אחר שהם בני חורין בעצם, ולא יגרע כחם מה שהם עבדים במקרה. ודבר פשוט הוא זה, ואין להאריך בדבר שהוא מבואר למי שהבין דבר זה.
Some ask: What benefit is the exodus to us, since we are subjugated under other kingdoms? What is the difference between the kingdom of Egypt from that of other kingdoms? This is silly, since when Israel left Egypt, they received goodness in there inherent selves, such that they became worthy themselves to become free people due to their greatness, and this great quality is inherent to the people of Israel, as they are fit to become free because of their greatness, and something accidental [or, tangential] cannot affect something which is inherent, since the people of Israel have this trait, as they are inherently free (and/or noble), and any subjugation is considered accidental [or, tangential]. This is because after the Holy One, blessed be He took Israel out of Egypt, and made them free people...this is the inherent status of Israel, and the greatness and significance of this cannot be nullified through exile, which is considered accidental [or, tangential]....
Question: In what ways do the four cups make the Seder similar to a symposium? In what ways are they different?
We learned in the mishna that even the poorest of Jews should not eat until he reclines. It was stated that amora’im discussed the requirement to recline. Everyone agrees that matza requires reclining, i.e., one must recline when eating matza, and bitter herbs do not require reclining. With regard to wine, it was stated in the name of Rav Naḥman that wine requires reclining, and it was also stated in the name of Rav Naḥman that wine does not require reclining. The Gemara explains: And these two statements do not disagree with each other: This statement is referring to the first two cups, and that statement is referring to the last two cups. However, it was not clear which two cups require reclining according to Rav Naḥman. Some say the explanation in this manner and some say it in that manner. The Gemara elaborates: Some say it in this manner, that the first two cups require reclining, as it is now that freedom begins. Since reclining is a sign of freedom, while discussing the exodus from Egypt it is appropriate to drink while reclining. By contrast, the last two cups do not require reclining, because what was already was. In other words, by this point one has completed the discussion of the Exodus and has reached the latter stages of the seder. And some say it in that manner and claim that on the contrary, the last two cups require reclining, as it is at that time that there is freedom. However, the first two cups do not require reclining, as one still says: We were slaves. The Gemara concludes: Now that it was stated so, and it was stated so, i.e., there are two conflicting opinions and it cannot be proven which two cups require reclining, both these sets of cups and those require reclining.
What is the source for the four cups? R. Yochanan, in the name of R. Benayah [said], they are parallel to the four terms of redemption: “Thus, say to the people of Israel, I am God, and [1] I will bring them out…[2] and I will save them…[3]and I will redeem them…[4]and I will take them to be My people…”(Exodus 6:6-7).
Rabbi Joshua ben Levi says, they are parallel to the four cups of Pharaoh: [1]“And the cup of Pharaoh was in my hand…[2] and I squeezed [the grapes] into the cup of Pharaoh [3] and I gave the cup of Pharaoh to the hand of Pharaoh…”(Genesis 40:11). [4] “And you will place the cup of Pharaoh in his hand…” (Genesis 40:13).
Rabbi Levi said, they are parallel to the four kingdoms [prophesied by Daniel; interpreted by the sages as being Babylon, Media/Persia, Greece, and Rome].
The sages say, they are parallel to the four cups of punishment that God will rain on the nations of the world in the future: [1] “take the wrathful cup of wine” (Jeremiah 25:15); [2] “the golden cup of Babylon is in the hand of God” (Jeremiah 51:7); [3] “for the cup is in God’s hand” (Psalms 75:9); [4] “a scorching wind shall be their cup” (Psalms 11:6; trans. JPS). What is “their cup”? Rabbi Avun says,
דיפלי פוטירין כדיפלי פוטירין אחר המרחץ וכנגד עתיד הקב"ה להשקות את ישראל ארבעה כוסות של נחמות (תהילים טז) ה' מנת חלקי וכוסי (תהילים כג) דשנת בשמן ראשי כוסי רויה והדין (תהילים קטז) כוס ישועות אשא תריין.
the drippings of poterion [a shrub that can be turned into a medicinal potion]; like a vial of poterion after a bath.
Parallel to [these cups]: in the future, the holy One, blessed be He, will cause Israel to drink four cups of comfort: [1] “God is my portion and cup” (Psalms 16:5); [2] “you anoint my head with oil, my cup overflows” (Psalms 23:5); and the verse [3-4] “I will raise the cup of salvations” (Psalms 116:13) counts as two.