A simple and practical model of the mind I like to use is to imagine it as comprised of three layers: at the root are our genetic tendencies; built on that is culture; and built on that is our consciousness.
Most of the behavior and capabilities of living beings is genetically encoded: our ability to use our senses to orient to the physical world, for example. Humans in particular have developed a rich cultural heritage, which are the behaviors, views, values, and cultural artifacts that have been preserved and past down from our parents and others who came before us. And we each have a consciousness that endows us with self-awareness, the ability to create a model of the world, and to adopt behaviors, views, and values that differ from those of others.
Significantly, our culture and genetic tendencies are "unconscious". We generally don't notice or question them, and we would struggle to articulate them. Some of the power of meditation and retreat is in separating ourselves from those around us (whether for 10 minutes or 10 days) so that we can become more conscious of how and why our mind is behaving in certain ways. That's the gateway to conscious change.
In a stable world where your circumstances are like those of your parents, the handed-down wisdom of culture takes precedence. Our elders generally know better than we do, and we would be well-served to listen to them. But in an unstable world, or one in which we are experiencing challenges that our culture hasn't equipped us to handle, we need to rely more on consciousness to find our own way.
Our conscious model of the world is necessarily an oversimplification. Our working memory has only a limited capacity to deal with objects and so we make absolute distinctions to separate "this" from "that" in a binary way. Our language is based on this ability to make distinctions, and our thought and language are interdependent and almost inseparable.
One of the most powerful distinctions our consciousness makes is our own sense of self. We feel that we're something entirely different from others, from the world around us. The more strongly that mental model is operating, the more we feel different from and isolated from others.
This normal mode of operating is called self-grasping: a sense that the self is something that truly exists, independently of everything else. Self-grasping is the root of our experience of fear, isolation, loneliness, and all our other sufferings.
Wisdom is a type of intelligence that sees through this self-grasping and thus protects our mind from fear, isolation, loneliness, and other sufferings. Among the many types of wisdom we can cultivate is the wisdom that knows we are never alone, and that the torment of isolation was always an illusion.
Being alone implies that there's no connection between ourself and others. Paradoxically, in our hyperconnected world, people face more loneliness and isolation than ever before. How can this be? Because loneliness has nothing to do with physical or verbal contact. Loneliness is a mental construct that arises when we believe we exist separately from everyone and everything else.
If we take this simple three-layer model of mind, we can understand a simple way to free ourself from loneliness. We can understand that we share a unifying layer with every other human being and indeed every other living being. Our thoughts, feelings, and actions seem to be "ours" but they generally bubble up from cultural or genetic tendencies. We think "I want to eat something sweet", for example, but that wish is not really ours: that wish is a genetic impulse (with some help from our gut bacteria). And that wish is no different from the same wish as experienced by countless other beings.
Our thoughts, wishes, and feelings are just types of information. And information is not bound or restricted by time or space in the way that physical objects are. Our body may be physically isolated from others, and our minds may also feel isolated. But wisdom sees through this misleading appearance.
The simplest way to break down the apparent distance between self and others is through empathy: feeling others happiness or pain as if it were our own. This natural, instinctive coupling of our emotions with others creates a bridge where previously we felt isolated.
Empathy arises naturally. It's the reason there are so many pictures of cute animals exchanged on the Internet. It's the reason we're moved by movies, news, and stories. But our instinctive empathy is still too limited and biased to free us fully.
Wisdom sees that we are never alone, never have been alone, and never could be alone. We are on the contrary made of the very same stuff that makes up others, and directly or indirectly we are in communion with them. Our genetic legacy is shared: we are family, however distant. And our cultural legacy is shared: our language, thoughts, values, and behaviors are generally more similar than different.
Our job in this life is to bring our consciousness more in line with reality so that we can stop struggling and start communing with others, for their sake and for ours.