The Buddha's Enlightenment is the central event in the religion of Buddhism, one of the world's oldest and most venerable of spiritual traditions. It is therefore an event profoundly significant in the history of ideas and spirituality, and is worth explaining, and I will seek to do so. What is this thing that the Buddha experienced under the Bodhi tree and led him to formulate this religion? Was it a realization of something that had always been deep within him?
I think the Buddhist answer to that question would be “no.” In my understanding, enlightenment is not a substance. It has no existence in that way. It doesn’t exist within us. Rather, enlightenment is sort of a change of state. The proper word for it, according to the monk Yuttadhammo Bhikku, who runs a YouTube channel called “Ask A Monk,” is a “realization.” It is the shift from one lens to another; from a false view of the world and the universe, and what their natures are, to a correct one. This is what happened to the Buddha under the Bodhi tree. He saw things for what they were. So if there is an element to this realization, it is really just part of the unity of a correct view of the world. But I will use the word element. Perhaps the most foundational element of this realization is that of “dependent origination.”
To illustrate what this concept means, take the example the sage Nagasena gave to King Menander of Bactria in the Milindapanha. If you take a chariot, and begin to remove certain parts of it, first the wheels, then the seat, then the axles, etc., at what point does it cease being a chariot? Are the disassembled parts of the chariot still making up a chariot, though a disassembled one? If so, then what is the essence of an axle, if it doesn’t consist in a chariot? The answer to that is that it isn’t an axle either, but yet another assemblage. And so on down the line, til you reach the atom, and even it is an assemblage. Nor can intrinsic essence be found in the functioning of phenomena. A chariot is not “that which rides.” As many other things do this as well. You could construct another assemblage that performs the same function of a chariot, but yet is not a chariot. Or maybe it is. The point is, the distinctions are arbitrary, and there is no foundational unity to anything. This means, too, that along with our own selves, our experiences are aggregates as well, and everything is merely the culmination of a certain “coming together.” When this arises, that arises, is a common way in Buddhism to explain dependent origination as simply as possible. And this is the universe. This knowledge of the universe is at the heart of the Buddha’s enlightenment. Seeing the world as it really works and as it really is. Which is that it is nothing but conditioned phenomena. When this arises, a universe arises. When a universe arises, planets arise. When planets arise, sometimes life arises. A gross over-simplification, but this is essentially the idea.
Of course, another way of looking at the Buddha’s Enlightenment is its role in the religion of Buddhism. To me, the Buddha’s Enlightenment is similar, in its function within a religious system, to Christ’s resurrection in Christianity. Both are “the good news.” The Third and Fourth Noble Truths, which are, to put them simply “There is a path to the cessation of dukkha and that this path has been found,” are the evangelion of Buddhism. They are the Buddhist equivalent of “he was dead, but he has arisen.” The announcement of the way to deliverance. The Enlightenment of the Buddha is in this sense the springboard event for Buddhist salvation. So this is another way of conceiving of the Buddha’s enlightenment, as the event which made the religion possible, and is thus the religion’s central event.
But regardless, enlightenment as a word can take a large variety of meanings, and even within Buddhism can have several different meanings and connotations. But as a personal experience, enlightenment is a noble goal for anyone to pursue.