Ignorance of the truth
The truth the Buddha taught is that everything which appears is a type of dhamma, a reality that is not self, not a being, not a person. All Dhammas that arise do so because there are conditions for their arising, such as attachment, anger, regret, unhappy feeling, jealousy, avarice, loving- kindness, compassion, seeing, hearing; all of these are different types of dhammas. There are different kinds of dhammas because they arise on account of different conditions. One erroneously takes attachment, anger, and other dhammas that arise, for self, for a being, for a person, and that is wrong view, wrong understanding. It is wrong understanding because those dhammas, after theyhave arisen, fall away, disappear, are subject to change all the time, from birth to death. The reason for erroneously taking dhammas for self, a being, or a person, is ignorance of the truth about dhammas.