In Thich Nhat Hanh’s presentation, “suffering” (dukkha) is not limited to obvious pain or misfortune, but names a pervasive uneasiness that marks conditioned existence. It includes direct physical and mental pain—illness, aging, death, grief, separation from what is loved, and the frustration of not getting what is desired—but it also reaches into more subtle forms of dissatisfaction and anxiety. Because all things are impermanent and lack a fixed, separate self, clinging to them inevitably generates a sense of instability and insecurity. This is why suffering is counted among the core marks of reality, alongside impermanence and non-self. Even pleasant experiences can carry a seed of unease, precisely because they are known to be fragile and short-lived.

Thich Nhat Hanh further clarifies this by distinguishing different dimensions of dukkha. There is the “suffering of suffering,” the raw pain of body and mind. There is the “suffering of change,” the distress that arises when what is pleasing inevitably alters or disappears. Finally, there is the “suffering of conditioned existence,” a deep, often hidden disquiet that underlies all experience so long as there is attachment to a separate, enduring self and to what cannot last. This last form is not always dramatic, yet it is the most pervasive, coloring even neutral or pleasant states with a subtle sense that something is not quite right.

Yet this teaching is not offered as a pessimistic verdict on life, but as a compassionate diagnosis. Suffering is called a “holy truth” because it is meant to be recognized, embraced, and examined with mindfulness rather than rejected or suppressed. When suffering is faced in this way, it becomes a teacher: understanding it leads naturally to insight into its causes and to the possibility of transformation and liberation. Thich Nhat Hanh thus portrays suffering as both the mark of a life lived in ignorance and attachment, and the very doorway through which understanding, compassion, and awakening can unfold.