就《阿含經》及其所代表之初期佛教而言，「無常即苦」之命題可謂基礎教理之緣起法與「一切行苦」命題之橋樑，亦作為解釋「一切行苦」乃至「苦聖諦」之關鍵。然而，於解釋上述教理時，學界鮮少深入析論「無常即苦」之命題──無論是對於「無常」與「苦」之關係、或是「苦」與「苦受」之關係，其見解均略欠清晰。 針對「無常即苦」之命題，本文將先就其邏輯結構來探討，一方面將確認其作為一全稱命題，一方面亦將指出其中「無常」與「苦」之順序不得顛倒。其次，本文分別就上述二點指出，若直接以「苦受」來解讀，「無常即苦」之命題將與某些《阿含經》經文相抵觸。再其次，本文認為「無常即苦」之「苦」，宜理解為「會導致生命體苦受之傾向」。故此一命題可表達如下：「對所有的 x 而言，若 x 為無常的，則 x 有會導致生命體苦受之傾向。」

The proposition “whatever is impermanent is dukkha (yad-aniccaṃ taṃ dukkhaṃ)” (henceforth abbreviated as YATD) plays a crucial role in early Buddhism. Preserved in the Pāli Nikāyas and the Chinese Āgamas, this proposition connects the basic doctrine of dependent origination with such propositions as “every compounded thing is dukkha” as well as with the Noble Truth of Suffering. However, we rarely find a detailed analysis of YATD in current scholarship. As a result, the meaning of ‘dukkha’ as well as the relation between ‘dukkha’ and ‘impermanent’ remains largely unclear. This paper discusses YATD in three steps. First, as to its logical form, I observe that YATD constitutes a universal proposition and that the order between the concepts of “impermanent” and “dukkha” is not to be reversed. Second, I argue against interpreting ‘dukkha’ simply as “feelings of suffering,” as this leads to problematic readings of YATD in the Āgamas. Third, I propose that ‘dukkha’ in YATD should be interpreted as a disposition that causes sentient beings the feelings of suffering. Based on this proposal, I suggest that YATD be read as “whatever is impermanent is of a disposition of causing sentient beings the feelings of suffering.”