The First Noble Truth is, “All is suffering.” Suffering here refers to the situation in which we cannot meet our desires or wishes. This truth implies that all life is suffering as long as we are dominated by greed, ignorance of the law, and hostility towards others. Our desires can never be fully satisfied.
The Second Noble Truth states, “The cause of sufferings is ignorance.” This means that suffering in life is caused by ignorance arising from our instincts, such as thirst, hunger, sex, and fear.
The Third Noble Truth states, “The extinction of ignorance is nirvana.” The sravakas took this to mean that ignorance could be extinguished only by quenching human desires.
The Fourth Noble Truth maintains, “The Way to Nirvana is by practicing the Eightfold Path.” The Eightfold Path consists of (1) right views (a correct understanding of the Four Noble Truths), (2) right thoughts (the ability to reflect on the Four Truths), (3) right speech (speaking only the truth and words of kindness), (4) right deeds (proper acts—that is, morality), (5) right livelihood (making a living without harming others), (6) right effort (or exertion), (7) right memory (memory of things beneficial to enlightenment), and (8) right concentration of mind (correct meditation).
The Twelve Interdependent Causes are: (1) ignorance, (2) predisposition, (3) consciousness, (4) “name and form” (an entity of mind and body), (5) the six sense-organs, (6) contact (touch), (7) sensation, (8) craving, (9) grasping, (10) existence, (11) birth, and (12) aging and death. (Since death results in “ignorance,” the whole cycle begins all over again.) Each cause is dependent on its predecessor. For instance, the first cause, ignorance, is the origin of all illusions. At the same time, it generates the second action of predisposition, which induces the third factor of consciousness (the first consciousness after conception takes place), which further produces the fourth cause of “name and form,” and so on. Since the world of illusions is gradually formed through this chain of actions, we will be able to attain enlightenment by eliminating these causes one by one, starting with the last cause.
It is generally said that the teaching of the Four Noble Truths is for sravakas, and that of the Twelve Causes is for Pratyekabuddhas.