The Five Aggregates are the Buddha’s explanation for why so many people find it hard to achieve Nirvana. The Buddha claimed that the Five Aggregates form the illusion of a distinct and permanent self. Indeed, the no-self doctrine is a refutation of the notion that the Five Aggregates form an enduring, unchanging self.
The Five Aggregates are:
Material Form (Rūpa): Form refers to four physical components that would be familiar to anyone who watched Captain Planet or read Empedocles or the I Ching: Earth, Water, Fire, and Wind.
Feelings Received From Material Form (Vedanā): This term refers to the reactions to sensations through the five faculties of perception: eyes, ears, tongue, nose, and body. These reactions can be pleasant, unpleasant, or neutral.
Perception (Samjñā): Perception, or cognition, occurs when a label is applied to a feeling. With perception comes categorization of feelings and the usage of language.
Mental Formations (Sankhāra): Deliberate thoughts are mental formations. Emotions emerge as a result of the labeling of feelings. Karmic predispositions and conscious/unconscious forces comprise the concept of Consciousness.
Consciousness (Vijñāna): Consciousness is the ongoing awareness of the four prior Skandhas. The complete perceiving-acting agent is expressed through Consciousness. The persistence of Consciousness can give the mistaken impression of an enduring self.
The conception of the Five Skandhas is vital to the Buddhist philosophical system. The Second Noble Truth diagnoses the cause of suffering as the clinging to the Five Skandhas as caused by the process of Dependent Origination. The Buddha’s teaching career made clear that greed, hatred, and ignorance are impediments to Nirvana. But greed for, hatred of, and ignorance of what, and in what context?
The Mahayana traditions view the Five Aggregates as both blessing and curse. While the aggregates perpetuate delusion, they also are the vessel for Buddha-nature itself.1
1Sutra of the Indestructible (Surangama), p. 89