No complex civilization can conduct its affairs, advance its interests, or sustain cooperation without a widespread reliance on factual truths. Engineering, medicine, law, and commerce all depend on correctly determining how things actually stand, so a society's practical success is tied to its respect for truth.
Facts are valuable to us because they are stubborn and independent of our wishes; their resistance to our preferences is what makes them reliable guides for action. We benefit from truth not when it flatters us but when it corrects us, giving us accurate footing against a world that does not bend to desire.
Most people do not value truth for its own sake but for the concrete benefits that knowing the truth brings them. This instrumental attachment is still genuine and sufficient: caring about outcomes forces one to care about the facts those outcomes depend on, even without any abstract reverence for truth.
A liar is still oriented toward the truth: he must know what is true in order to deliberately conceal it, so he keeps track of reality. The bullshitter, indifferent to whether his statements are true or false, abandons any connection to the facts and is therefore the greater enemy of truth.
A person cannot have an accurate sense of self without first acknowledging truths about the world they inhabit, since identity is partly constituted by one's actual circumstances and relations. Denying external reality corrupts self-understanding, making the pursuit of truth a precondition for a coherent, reality-based self.
Viewing facts as what we did not make and cannot alter by will reveals a boundary between ourselves and the world. Recognizing this boundary is what distinguishes a serious person from someone who treats the world as infinitely pliable to his own fantasies and assertions.