Those who like it can study the Abhidhamma as an addition to the meditation. The prefix ‘abhi‘ means ‘transcending’ or ‘higher’; in this case the word ‘dhamma‘ has the meaning of ‘truth or teaching’. So together the approximate meaning is ‘higher teaching’.
Bhikkhu Bodhi writes in his translation of the Abhidhammattha Sangaha (a summary of the Abhidhamma written by Acariya Anuruddha around the 11th-12th century AD):
In the Suttas the Buddha regularly makes use of conventional language (voharavacana) and accepts conventional truth (sammutisacca), truth expressed in terms of entities that do not possess ontological ultimacy but can still be legitimately referred to them.
Thus in the Suttas the Buddha speaks of “I” and “you,” of “man” and “woman,” of living beings, persons, and even self as though they were concrete realities.
he Abhidhamma method of exposition, however, rigorously restricts itself to terms that are valid from the standpoint of ultimate truth (paramattha-sacca): dhammas, their characteristics, their functions, and their relations..
So in the Abhidhamma all concepts, which are still accepted in the sutta for easier communication, are not used anymore.
Thus in the Abhidhamma all such conceptual entities provisionally accepted in the Suttas for purposes of meaningful communication are resolved into their ontological ultimates, into bare mental and material phenomena that are impermanent, conditioned, and dependently arisen, empty of any abiding self or substance.
The Abhidhamma ‘transcends’ the conventional character of the sutta. Take a car as an example. Is it still a car if you loosen every screw and put every part on the ground separately?
In the ultimate sense, a car is not a reality. We call the conglomerate of material phenomena assembled in a specific form with specific properties ‘car’. It is an agreement, a convention.
The Abhidhamma would not speak of ‘car’, but of these smallest phenomena and their mutual relations and properties.
In the first book of the Abhidhamma (the Dhammasaṅgāni) all the smallest building blocks are listed, and thus the smallest components of reality are represented. This is the analysis.
In the last book (the Pattahāna) the conditional relationships, the connections between these building blocks, can be found. This is the synthesis.
These two aspects together, the analysis and the synthesis, reflect the uniqueness of the teaching of the Buddha.
Namely that everything is transient and without self, but that it is still worthwhile to develop morality, concentration and wisdom.
On the one hand it is thus demonstrated that ‘we’ and the outside world are nothing more than a hotchpotch of loose, transient moments.
Moments that arise and perish on their own.
A whole lot of these mental and material phenomena together are nothing more than a convention, an ‘I’ without actually being an ‘agent’ or something permanent.
On the other hand, it is made clear that these moments do influence each other and that you can bring about change in the conditions through developement of the mind (call it free will).
That is why it is important to behave morally, so that the right conditions for concentration arise. And to develop concentration, so that the right conditions for wisdom arise. And to develop wisdom, so that the right conditions for liberation, for a truly happy life arise.
To emphasize, you cannot change the moments of the present, you are always too late for that. You can only try to change the conditions, the conditions, so that the next moments of consciousness are of a higher value.