Near the end of Il Saggiatore, the first book Galileo had published since the ban of 1615, he dispensed with the sarcastic attacks on Sarsi, and made some philosophical points that were new. These would come back to haunt him later:

I must consider what it is that we call heat, as I suspect that people in general have a concept of this which is very far from the truth. For they believe that heat is a real phenomenon, or property, or quality, which actually resides in the material by which we feel ourselves warmed. Now I say that whenever I conceive any material or corporeal substance, I immediately feel the need to think of it as bounded, and as having this or that shape, as being large or small in relation to other things, and in some specific place at any given time; as being in motion or at rest; as touching or not touching some other body; and as being one in number, or few, or many. From these conditions I cannot separate such a substance by any stretch of my imagination. But that it must be white or red, bitter or sweet, noisy or silent, and of sweet or foul odor, my mind does not feel compelled to bring in as necessary qualities. Without the senses as our guides, reason or imagination unaided would probably never arrive at qualities like these. Hence I think that tastes, odors, colors, and so on are no more than mere names so far as the object in which we place them is concerned, and that they reside only in the consciousness. Hence if the living creature were removed, all these qualities would be wiped away and annihilated.

Very deep stuff, and strangely—even suspiciously—ahead of its time; although at the same time, far behind the Jovians’ understanding of things. Galileo knew perfectly well that he was describing his state of mind before Aurora’s tutorials; that was something he wanted to do here, just to clarify his thoughts in their evolution. He wrote as he had always written. That it was also true that what he was calling effects of consciousness extended beyond heat and tickling and taste and colors to fundamental qualities like number, boundedness, motion or rest, location or time—that was something he knew but still could not feel. It remained a conundrum to him, part of the feeling of anachronism always disorienting him.

That these sentences of Il Saggiatore could be construed as denying the reality of the transubstantiation of the bread and wine into Christ’s body and blood, during the sacrament of Communion—that they were, in other words, according to the Council of Trent and the doctrinal law of the Holy Church, heretical statements—did not occur to Galileo, or to any of his friends and associates.

But it did to some of his enemies.

In the midst of all this excitement, and Galileo’s preparation for another journey to Rome, the weekly letter would arrive from Maria Celeste:

As I have no bedroom of my own, Sister Diamanta kindly allows me to share hers, depriving herself of the company of her own sister for my sake. But the room is so bitterly cold, that with my head in the state it is in these days, I do not know how I will be able to stand it there, unless you can help me by lending me a set of those white bed-hangings which you will not want now. I should be glad to know if you could do me this service. Moreover, I beg you to be so kind as to send me that book of yours which has just been published, so that I can read it, as I have a great desire to see what you have said.

These few cakes I send are some I made a few days ago, intending to give them to you when you came to bid us adieu. Sister Arcangela is still purging herself, and is much tried by her remedies, especially the two cauteries on her thighs. I am not well myself, but being so accustomed to ill health, I do not make much of it, seeing too that it is the Lord’s will to send continual little trials like this. I thank Him for everything, and pray that He will give you the highest and best felicity. To close I send you loving greetings from me and from Suor Arcangela.

Sire’s Most Affectionate Daughter,

S. M. Celeste

P.S. You can send us any collars that want getting up.

Galileo heaved heavy sighs as he read this. He arranged to have blankets sent over to the convent, and with them a letter asking Maria Celeste if there was anything else he could do. He was sure to go to Rome sometime soon to meet with the new pope, he told her. He could ask the Sanctissimus for something for the convent, perhaps some land to generate income; perhaps a direct endowment, or some simpler form of alms. What did she think the nuns would like most?

Maria Celeste wrote back to say that alms would be very well, but what they needed most was a decent priest.

Galileo cursed when he read this. “Another priest. They need food!”

Her letter went on to explain:

Since our convent finds itself in poverty, as you know, Sire, it cannot satisfy the confessors when they leave by giving them their salary before they go. I happen to know that three of those who were here are owed quite a large sum of money, and they use this debt as occasion to come here often to dine with us, and to get friendly with several of the nuns. And, what is worse, they then carry us in their mouths, spreading rumors and gossiping about us wherever they go, to the point where our convent is considered the concubine of the whole Casentino region, whence come these confessors of ours, more suited to hunting rabbits than guiding souls.

Galileo couldn’t be sure if she knew what hunting rabbits meant in Tuscan slang, or if she actually meant hunting rabbits; but he suspected the former, and laughed, both shocked and pleased at her sophistication.

And believe me, Sire, if I ever began telling you all the absurdities committed by our present confessor, I should never be done, for they are as numerous as they are incredible.

She was so smart. Surely she was her father’s daughter, for the acorn never fell far from the tree (except when it did, as with his son). Indeed it sometimes seemed to Galileo that Maria Celeste was the only sane and competent nun in the entire convent, carrying the other thirty on her slim shoulders, every day and every night: supervising the cooking, nursing their ills, making their preparations, writing their letters, and keeping her sister out of the wine cellar, which apparently was a new problem to add to all Arcangela’s others. Maria Celeste’s letters to Galileo were almost always written in the seventh or eighth hour of the day, which began at sunset, meaning she was getting only a couple of hours of sleep before the bell rang for compline, and their predawn prayers would begin. The relentless routine was beginning to tell on her, Galileo could see when he took his baskets of food over. She had no meat on her bones, there were always dark rings under her eyes, and she complained of stomach trouble; she was losing her teeth; and she was just twenty-three years old. He feared for her.

And yet still her letters came, each one exhibiting intense care to make it shapely on the page, utilizing her characteristic clear hand with its big loops, and the flowing proud signature at the bottom.

But so often filled with trouble. One morning Galileo watched himself opening her latest letter, full of a sudden dread, and started to read, then shouted with alarm. “Oh no! No! Jesus Christ! Pierrrrrrr-a! Fill a basket, and find Cartophilus and tell him to get Cremonini ready. Their mother abbess has gone mad.”

This worthy was no longer Vinta’s sister but another woman—small, dark, and intense. “She’s slashed herself thirteen times with a kitchen knife,” Galileo told La Piera as he pulled on his boots, finishing Maria Celeste’s letter as he did so. “These people are not competent to live!” he exclaimed bitterly. “They need an income, some property, a trust—anything!”