愛的雙眼是盲目。愛的內心是無我。愛的身體是瘋狂。愛， 不僅是一種個人內在心理慾望的能量，更是一種社會交換經濟中 複雜又微妙的慾力跨界流動關係。人世間的愛常是小小寂寞城內 「達達的馬蹄聲」，總引來許許多多錯誤的美麗期待。然而，如 果/愛，真能夠卸下一件件幻見的華麗或美德外衣，這世界將會 如何重新運行？問世間，愛爲何物？從字源的角度而言，「愛」 在希臘文中，包含四種完全不同的意義：自我愛慾(Eros)共 在情感（Philia)、對人群的愛（Caritas )與對上帝或形上的愛 (Agape)。筆者相信具有干擾性與不確定性的假設語氣「如果」， 可以突顯出「愛」內在晶體結構性的多元差異、張力與衝突。因 此，如果/愛，究竟是無私奉獻？抑或盲目犧牲？如果/愛，究 竟是愛「自己」抑或「他者」？如果/愛，究竟是愛「他者」心 中的「自己」？抑或是愛「自己」心中的「他者」？如果/愛， 究竟是內心匱乏的永遠塡補？形上滿溢的無盡回應？抑或是生 命當下融合/分裂的抗戰？筆者首先介紹爲何「如果/愛」 (If/Love)是一種開放性慾望經濟體（a general economy of desire)，而「當一愛」（When-Love)爲何是一封閉性慾望經濟 體（a limited economy of desire )，作爲本文的前言。本文主要會 從「如果/愛」的開放性慾望經濟體中，試圖探討當代理論中三種（匱乏式、滿溢式與分裂式）「愛」的不同經濟結構，與其各 別可能產生的侷限與問題。

What is love? Tradition tells us love is blindness, love is selflessness, love is madness. In contemporary theory, love is not just a person’s emotion of strong affection or psychic energy, but a complicated “desire economy” circulating between borders of interpersonal relationships in our societies. In ancient Greek, the word “love” had four meanings: Eros (a passionate, usually sexual desire), Philia (a love among family and friends), Caritas (a love of fellow man, charity), and Agape (a divine, unconditional or pure love). I use the subjunctive “if,” to indicate the sort of interruption and uncertainty that can unfold the multiplicity, tension as well as conflicts within the intrinsic desire structure of love. That is: does love suggest a selfless devotion or blind sacrifice? Does love indicate a love of others in the world or of the others imagined by the self? Is love an endless supplement to the mental lack, unceasing responses to the overflow of metaphysical desire, or the eternal split between oneness and separation with the Other? This article, first distinguishes two economies of desire: 1) “if/love” as “a general economy of desire,” and 2) “when-love” as “a limited economy of desire.” Second, within a if/love general economy of desire, it examines three kinds of limited desire economy of love (and their limits): a Zizekian lack-oriented economy of love, Levinasian overflow economy of love, and Deleuzian schizo economy of love. Finally, it draws salient conclusions for theoretical and literary presentations of interpersonal relations and feelings.