An actual blur that directly modifies multiple pixel values cannot be reversed. Things like swirls and motion "blurs" potentially can be - but I wouldn't even call those blurs as they are more of a directional transformations.
Hmm, given we know it's a face, and we know their skin tone from the rest of the photo, I wonder what a computer would be able to reconstruct... Any papers about this?
"For example, an algorithm may analyze the relative position, size, and/or shape of the eyes, nose, cheekbones, and jaw" etc, says Wikipedia.
You can reconstruct a plausible face by deblurring, ie. one that looks sharp and human. But if you want to identify someone having a plausible picture with a pair of eyes in a plausible position doesn't help, you need a fairly accurate assessment of the distance between the correct eyes, and that's susceptible to loss of information during blurring.
