But for example birth, aging and death are material process. Matter doesn't know anything, is consiousness what knows. What does it know? It knows sense impressions as back pain and concepts like "I'm diying, I'm old, I can't do things".
It's because these kind of consiousness that arise dukkha-vedana.
If my body is dying, but this phenomena doesn't produce any painful sense impression, and does't produce any painful mental concept then I have no problem at all with body diying.
How can I perceive dukkha if is not by means or in the dimension of vedana?
"Now what is the noble truth of suffering (dukkha)? Birth is suffering, aging is suffering, death is suffering; sorrow, lamentation, pain, distress, & despair are suffering; association with the unbeloved is stressful; separation from the loved is suffering; not getting what one wants is suffering. In short, the five clinging-aggregates are suffering.