The four references as taught by the Lord Buddha:
The body includes the six senses: eyes, ears, nose, tongue, body and mano. The body includes the brain. The brain is not the Citta or mind. The mind is located in the chest.
Feelings are summarized into three categories: Pleasant, unpleasant, neutral. They include physical feelings and mental feelings. Mental feelings can also be seen as emotions.
Citta the mind is consciousness. The Citta flows in and out of the five aggregates. The Citta flows through Mano. Mano is the Citta’s consciousness.
Dhamma’s are the phenomena experienced through the six senses by the Citta.
The aim is to be aware of these four frames of reference by tuning in with mental presence and mental observation. To seek wisdom through investigation. Eventually to comprehend that these four frames of reference are only: Annicang, Dukkhang and Anatta. I.e impermanent, stressful and Not-self.
Thorough investigation of these four frames of reference yields true wisdom and knowing of nature. The human being is a mass of aggregates over which the Citta has no control. Mano consciousness is that which creates birth and death hence Kamma and Vipaka.
Through mano consciousness our knowing links to the next birth. The problem lies in the fact that our knowing does not understand and is ignorant of the truth: that body, feelings, citta and Dhamma’s are not self. Our knowing craves existence because it is not aware of Nibbana.
The aim of the practice of Sati is to demolish this very ignorance. To inject wisdom into our knowing so it destroys ignorance and to stop craving. This leads to liberation and finally bliss.
Sati in a nutshell.