This question is more than idle curiosity. Understanding how meditation works can greatly assist you in becoming a better meditator. Once you know how this practice can change the state of your being, you can clarify your intention which cn lead to a more powerful mediation.
The information shared here is an accumulation of knowledge from various teachers coming from different traditions and sciences. The way these concepts are explained is therefore completely unique and may not strictly fit into any one tradition. They are instead my interpretation of what is expressed through different traditions.
In order to understand how meditation works, it is necessary to ask the question -Why do we meditate? It is safe to say that we practice meditation for largely the same reason as we do most things in our life – to reduce suffering and increase happiness. This is why we eat, sleep, socialise, work, make art, have children and so on. That is everything we do in life is to gain happiness.
The question that immediately springs from this answer is – What is happiness?
Happiness is the natural, original quality of the mind.
We learn from advanced meditators in every tradition that the joy and serenity achieved through single-pointed awareness exceeds any state of happiness in ordinary, waking life. Modern neuroscience has been steadily catching up with this realization. For example a study was conducted over 12 years ago which scanned the brain of a Buddhist monk who had thousands of hours of meditation experience. It was found that during deep meditation, his left pre-frontal cortex was highly stimulated in relation to his right side which gives him a massive capacity for happiness and a lower tendency toward negative mental states. Brain scans of other advanced practitioners yielded similar results suggesting that meditation can change the functioning of the brain to facilitate extraordinary states of bliss.
Advanced meditators are able to access a natural, unadulterated state of mind prior to the influence of belief-systems, outlooks and worries that are conditioned through perceptual thinking. In our normal life, we go through varying periods of happiness and sorrow. But even our happiest experiences are some form of suffering in relation to this natural state accessible through deep meditation. This insight can be quite confrontational and disorienting but if we think about it deeply, it can become quite transformative. It shows us that this highest state of happiness is accessible to everyone and our mental state is not prey to external circumstance as many of us believe. It helps us see that happiness is a skill that can be developed and meditation is one of the most effective ways of honing this skill.
So to summarise, the reason we meditate is the same reason that we do everything in life – that is to be happy.
But happiness is not some mental capacity we develop – it is actually a natural quality of the mind which we can unveil if we can drop the mental patterns that act to block us from this natural quality of mind. So with that in mind – now go get some cushion time.