Does Nirvana exist?

A Buddhist friend recently posted something from the Buddhist philosopher, Buddhaghosa, which wrote in the very influential book, Visuddhimagga (The Path of Purification). In this book, there is a discussion on the Third Noble Truth. The Third Noble Truth is about Nibbana (or Nirvana). I will excerpt the passage as follows:

[DISCUSSION ON NIBBĀNA] 67. [Question 1] Is Nibbāna non-existent because it is unapprehendable, like the hare’s horn? [Answer] That is not so, because it is apprehendable by the [right] means. For it is apprehendable [by some, namely, the nobles ones] by the [right] means, in other words, by the way that is appropriate to it, [the way of virtue, concentration, and understanding]; it is like the supramundane consciousness of others, [which is apprehendable only by certain of the Noble Ones] by means of knowledge of penetration of others’ minds. Therefore it should not be said that it is non-existent because unapprehendable; for it should not be said that what the foolish ordinary man does not apprehend is unapprehendable. 68. Again, it should not be said that Nibbāna does not exist. Why not? Because it then follows that the way would be futile. [508] For if Nibbāna were non-existent, then it would follow that the right way, which includes the three aggregates beginning with virtue and is headed by right understanding, would be futile. And it is not futile because it does reach Nibbāna.