The Daodejing opens by disqualifying itself: the way that can be spoken of is not the constant way, the name that can be named is not the constant name. What follows is eighty-one short chapters that proceed by image, paradox and negation rather than by definition, and the form is a consequence of the opening claim rather than a stylistic preference.
The Tao is described as prior to heaven and earth, as the mother of all things, as empty yet inexhaustible, and as something that can be relied on but not grasped. It generates without possessing, acts without claiming credit, and accomplishes without striving. Water is its recurring image, because water benefits everything, contends with nothing, occupies the low places everyone else avoids, and wears away what is hardest.
Several negations are essential to understanding what is being claimed. The Tao is not a creator standing outside the world: it is immanent, and things arise from it as a process rather than by an act of will. It is not addressed: the Daodejing contains no prayers and the Tao has no preferences to be appealed to, and a much-quoted line says that heaven and earth are not humane and treat all things as straw dogs. It issues no commandments: there is no revealed law, and the ethical content of the text is advice about how things go rather than instruction about what is owed.
The associated cosmology is generative rather than fabricated. The Tao produces one, one produces two, two produce three, three produce the ten thousand things, a sequence read as the undifferentiated giving rise to polarity and polarity to the world.