To understand self-transcendence it is necessary to understand the concept of self. The separate individual self is an illusion created by our own activity. This activity may be observed and understood directly, thus the admonition to be vigilant, to merely observe one’s present activity, and thereby go beyond, or transcend that habitual activity.
There is no admonition to “work on oneself”, and it is to this error that the parable of the dog’s tail refers.
Buddhism is about realisation of unconditional happiness, truth or reality – this is not achieved by thinking. The felt sense of a separate mortal self is suffering in its primary form. The sign and symptom of suffering is habitual thinking. The self and its thoughts are the activity which places the limit upon happiness.
All thoughts, actions, emotions, perceptions and conceptions are temporary, dependent upon the body-mind and never the equivalent of perfect happiness.
Unconditional happiness is not contained within body or mind. Rather we are “within” happiness, reality or truth.
This is what Buddhism teaches. The realisation of truth or happiness is not accomplished by wearing amulets made of clay, chanting hymns or by any effort to improve the self. It is realised through the conscious transcendence of ego-self in every present moment. This is spirituality, nothing less.