The Four Noble Truths and the Eightfold Path constitute an eminently rational method for curing spiritual malaise that is similar in approach to the method used by medical science in curing physical illness. In addition, the Buddha’s system agrees fundamentally with the scientific approach in studying phenomena – natural, cultural, or social – to arrive at general principles, work in accord with these principles, and apply them to the creation of human ideals. On the basis of an understanding of the principle of cause and effect, the Buddhist system accurately identifies mental actions and fate as the effects of causes and applies this principle to the creation of an ideal spiritual condition. This is the basic meaning of the Four Noble Truths.
Basic Buddhist Concepts

Ignorance, the first link, means lack of knowledge of correct Buddhist principles and the truths of the world and of human existence. Failure to know the truth leads to faulty judgments and misdeeds, which bring on failure and grief. Ignorance is the fundamental cause of errors and the misfortunes they yield.

Action, the second link, is the mistaken conduct caused by ignorance. It is identical with karma. Lacking a correct view of the world and humankind, human beings think, judge, and act wrongly. Instead of ending when committed, good and bad actions persist and accumulate to reappear as causes of later actions. In other words, good and evil deeds that go undetected by others nonetheless have karmic effects on the perpetrator. In the Buddhist context, the term action means both the present deed and the accumulated deeds of the past. The sum of past deeds is of especially great importance in the Twelve-linked Chain of Dependent Origination.

Not only actions resulting from ignorance but also general experiences, whether good or bad, physical or spiritual, become a latent force constantly exerting an influence on thought and conduct. An accumulation of good deeds makes it easier to perform still more good deeds, while an accumulation of evil acts offers little to hinder the perpetration of further wickedness and aggravates the difficulty of turning in the direction of good. Each individual has a store of past actions and experiences that manifest themselves in various ways. They determine memory or intellectual capacities, temperament, skills or talents, and physique and health – in short, the total person. A person is the total of all he or she has done in the past, and action in the Twelve-linked Chain of Dependent Origination means the total of past mistaken experiences caused by ignorance within the cycle of transmigration.

In the context of the Twelve-linked Chain of Dependent Origination, consciousness signifies perception as a whole, which is based on and incorporates past experiences. Human awareness is not pure but is colored by past actions. It looks through a filter tinted by preconceptions derived from past experiences, preconceptions that make totally objective judgment and understanding impossible. Since consciousness includes elements derived from actions based on ignorance, its perceptions and their results are always mistaken.
Basic Buddhist Concepts