O me! what eyes hath Love put in my head,
Which have no correspondence with true sight;
Or, if they have, where is my judgement fled,
That censures falsely what they see aright?
If that be fair whereon my false eyes dote,
What means the world to say it is not so?
If it be not, then love doth well denote
Love’s eye is not so true as all men’s: no,
How can it? O! how can Love’s eye be true,
That is so vexed with watching and with tears?
No marvel then, though I mistake my view;
The sun itself sees not, till heaven clears.
O cunning Love! with tears thou keep’st me blind,
Lest eyes well-seeing thy foul faults should find.
In plain English
Love has given me eyes that don't work right—they see something as beautiful that the whole world says isn't. Either my eyes are broken, or my judgment is broken and I'm calling ugly things fair.
The speaker spirals through the logic: if what I love is really fair, why does everyone else say it isn't? If it isn't fair, then love itself is just bad eyesight. And of course love's vision can't be trusted—it's clouded by obsession and tears.
By the end, he accuses love of a deliberate trick: love keeps him crying and blind on purpose, so he won't see the faults in the dark lady. Love uses his own tears as a weapon to keep him from seeing the truth.
