The American science writer Kitty Ferguson wrote a fairly good double biography of Tycho Brahe and Johannes Kepler titled The Nobleman and His Housedog. Tycho Brahe and Johannes Kepler: the Strange Partnership that Revolutionised Science (review, 2002). Tycho is obviously the noble but Kepler as a housedog? Isn’t that rather insulting? It would be if it wasn’t for the fact that the description is from Kepler himself. In 1597, Kepler wrote an unpublished essay, in Latin, in which he describes himself in quite a lot of rather rambling detail. It is here that we find him calling himself a dog, I don’t have a copy of the Latin original but in the German translation the term is Haushund, which is what I suspect Ferguson presents in English as housedog, I think pet dog is a better translation. A year earlier, he had made some notes describing his grandfather and his parents as an appendix to their horoscopes. In what follows, I present an English translation, from the German of the passage, where he describes himself as a pet dog and excerpts from the descriptions of his immediate family.
I have in every sense the nature of a dog. I am a spoilt lap dog. My body is agile, skinny, well proportioned. My way of life is identical: I enjoy gnawing on bones, bread crusts delight me, I am greedy, I lack discipline, I seize whatever I happen to see. I drink little. I am satisfied with the least possible. I continuously pester my superiors like a pet dog. I am always loyal to others, I serve them, I’m never cross with them if the criticise me, I am always prepared in every way to win their favour again. On my own accord, I research everything in the sciences, the state, in household affairs, in the slightest tasks. I am always on the go and strive after those who undertake something, in that I pursue and research it as well. I am impatient in my dealings and all too often I greet those, who come into the house no differently than a dog. Whenever anybody snatches even a little from me, I grumble and create a commotion like a dog. I hold on tenaciously, follow those who behave badly, and naturally I bark. I also snap and have a nasty retort on my tongue. Many therefore hate and avoid me, and my superiors are fond of me like the people living in a house are fond of a good dog. Just like a dog, I afraid of being bathed, getting wet and being washed. Put simply, within me dwells an uncontrolled recklessness but directly alongside it a fear of life. Daring in dangerous situations is far from my nature. That is more or less enough, about anger, desire, and about the things for which one is mostly admonished.
This is not a pretty portrait that the good Johannes presents of himself but the one he presented a year earlier of his family, based on astrology, was not better. His grandfather Sebald, a judge in the Imperial City of Weil, he describes as follows:
He was eloquent when meeting the uninformed, he is more content as dictator and more content as leader than as reporter.
Of his father he has the following to report:
My father, Heinrich, was born in 1527 on the 19 January. Saturn destroyed everything, producing a heinous, brusque, argumentative, and not least one destined to die a terrible death. The position of the stars multiplied his malice, plunged him into poverty, however he found a rich wife. He was a trained artillery man, had many enemies and a marriage full of strife. False and vain striving for honour and hope drove both of them, also wanderlust.
This is followed by list of his father’s disappearances to serve as mercenary, and his numerous business failures. Johannes closes with a hard judgement.
Just as a window shutter gets damages, so my father injured himself on his return home, he treated my mother in the same way and finally he went into exile and died.
Heinrich is followed by his younger brother, Johannes’ Uncle Sebald, who appears even worse than the father:
His brother Sebald was born 13 November 1552, was a conjuror, Jesuit priest with the first and second ordination, sordid in life: because he was Catholic but pretended to be Lutheran. He died young of dropsy after many illnesses. He found a noble and rich wife but with many children. He caught the gallic disease [syphilis], was nefarious and hated his fellow citizens.
Strangely he ends his account of this rapscallion with the following:
He was educated in the humanities and a good companion.
We now arrive at his mother:
My mother, Katharina Guldenmann was born 8 November 1547
This is then followed by a discussion that the dates of her birth and her marriage didn’t add up and the contradictory claims made by her mother and her grandfather. Now comes Johannes’ negative judgement over his mother:
She is small, lean, black, with acerbic humour, argumentative, and has an unpleasant personality.
Before this he had already written, “she is very like me”!
He does, however, say that she had it hard:
1589, she was handled very badly by her husband. My mother was also beaten by her parents, even when she was pregnant, however, she escaped.
There now follows a claim from Kepler that is given in almost all biographies:
My conception can be calculated for 16 May at 4:37 pm. My mother had a premature birth, and my sickliness awakes the suspicion that the shortened pregnancy was the cause.
This is based on his calculation of the time between the wedding and his birth but there is of course the suspicion that his mother was already pregnant when she married.
All of the above taken together create the impression that in his middle twenties, at the time he wrote is Mysterium Cosmographicum, reflecting on himself and his family Kepler was not a happy puppy!