Three Passions l Have Lived For

Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search for knowledge, and unbearable pity for the suffering of mankind. These passions, like great winds, have blown me hither and thither, in a wayward course over a deep ocean of anguish, reaching to the very verge of despair.

I have sought love, first, because it brings ecstasy — so great that I would often have sacrificed all the rest of my life for a few hours of this joy. I have sought it, next, because it relieves loneliness — that terrible loneliness in which one shivering consciousness looks over the rim of the world into the cold unfathomable lifeless abyss. I have sought it, finally, because in the union of love I have seen, in a mystic miniature, the prefiguring vision of the heaven that saints and poets have imagined. This is what I sought, and though it might seem too good for human life, this is what — at last — I have found.

With equal passion I have sought knowledge. I have wished to understand the hearts of men. I have wished to know why the stars shine…… A little of this, but not much, I have achieved.

请问：I have wished这里为什么要用现在完成时态？