[Kepler] provided a running account of his feelings about the work, including the kind of emotional remarks that no modern scientist would consider publishing.
As an example she offers the following quote from Kepler's Astronomia novae
If I had embarked upon this path a little more thoughtfully, I might have immediately arrived at the truth of the matter. But since I was blind from desire I did not pay attention to each and every part [...] and thus entered into new labyrinths, from which we will have to extract ourselves. (Kepler 1609, pp. 455-456)
Gentner provides a few other choice quotes too - hence I think that if Kepler were around today, he'd be blogging.