Boyle's pump stood in a house in Oxford, Descartes computed the rainbow alone in the Dutch countryside, and Galileo saw Jupiter's moons through the only good telescope in the world, so the obvious question is how any of that became something the rest of Europe could use.
The previous lessons have produced a stock of results and one unmet condition, stated two lessons ago: an experimental fact has to survive other hands. Meeting it took a set of institutions and conventions built deliberately between roughly 1640 and 1670, and they are as much a part of the change this subject describes as any telescope. What follows is about how a private observation was turned into a public fact, and about the best objection anyone made to the whole arrangement.
The switchboard
Before there were societies there was correspondence. The central node was a Minim friar in Paris, Marin Mersenne, who from the 1620s until his death in 1648 wrote to and received letters from something like 140 correspondents across Europe, including Descartes, Galileo, Torricelli, Hobbes, Fermat, Pascal and Huygens.
What Mersenne did was more than pass letters on. He posed problems to several people at once, circulated an answer to the person best placed to attack it, and arranged for experiments to be repeated in another city. When Pascal's brother-in-law climbed the Puy de Dôme, the design and the result travelled through channels of this kind. A network of that sort is fragile in one specific way: it depends on a person. Mersenne died and it dissolved.
Alongside the letters ran the older system of patronage. Galileo named Jupiter's moons after the Medici and got a court appointment for it, and disputes at court were adjudicated by the patron's favour rather than by the evidence, since a client's credibility was a function of his standing. That arrangement can produce excellent work and it cannot produce a stable public fact, because the verdict changes when the patron does.
Why publish at all
There is a prior question that a modern reader skips: why tell anyone. The craft tradition, from which most instrument makers came, kept its knowledge secret because secrecy was its living. Mathematicians in sixteenth century Italy fought public problem-solving contests for university chairs and concealed their methods for the same reason. A discovery was an asset, and giving it away was giving away the asset.
The transitional device is the anagram, and it is a wonderfully exact expression of the dilemma. Galileo announced the phases of Venus in 1610 as a scrambled Latin sentence, which established that he had something on a date without saying what. Huygens did the same in 1656 for the ring of Saturn, releasing the solution three years later when he was ready. Hooke published ceiiinosssttuv in 1676 and revealed it in 1678 as ut tensio sic vis, as the extension so the force, which is the law of the spring.
Example. What is the anagram trading, and what replaced it?
It trades disclosure for a dated claim. The author gets a public, verifiable record that he possessed the result at a certain moment, without letting a rival use it, which is exactly what a secretive practitioner wants. What replaced it is better in every respect for everyone but the author: a journal that prints the result in full, with a date on the issue. Publication buys the same priority and pays for it by handing the content over, and it only becomes attractive when the currency changes, when a reputation built on published results is worth more than the private use of an unpublished one. That change is what the institutions of the 1660s brought about, and once it had happened the anagram disappeared within a generation.
Now you. Newton had his method of fluxions by 1666 and first let anything of it appear in print in 1693. Leibniz reached his version of the calculus in 1675 and published in the Acta Eruditorum in 1684. What does that pair of dates say about what a publication system rewards?
Answer
Newton was about nine years earlier in discovery and about nine years later in print, and the resulting priority dispute poisoned relations between British and Continental mathematics for a century, with the British sticking to Newton's notation long after Leibniz's had proved more workable. The system rewards publication, not possession, and it does so deliberately: a result nobody can read does nothing for anyone else, so the incentive is set to pull it out. Newton's reasons for delay were partly temperamental and partly rational, since his first paper, on colours in 1672, drew criticism from Hooke that he found intolerable. The episode shows both sides of the arrangement. It converts secrecy into disclosure, which is its purpose, and it creates a new kind of quarrel, over who was first, which barely existed when knowledge was a private asset.
An institution with rules
On 28 November 1660, after a lecture by Christopher Wren at Gresham College, a group of twelve agreed to meet weekly to promote experimental learning. Charles II granted a charter in 1662 and a second in 1663, which lists 131 original fellows. The society took as its motto nullius in verba, on no one's word, a phrase from Horace that reads as a direct repudiation of the method of settling arguments described in the first lesson.
The practices matter more than the charter. Experiments were performed at the meeting, in front of everyone, and Robert Hooke was appointed Curator of Experiments in 1662 and required to bring three or four to each weekly meeting, which is a punishing schedule and a revealing one: the society's business was to make things happen in the room rather than to discuss reports of them. Results were entered in a register book with a date, so a claim of priority could be checked against a record the claimant did not control. Attendance was recorded, which turns the audience into named witnesses.
Two models
The Académie Royale des Sciences, founded in Paris in 1666, made the opposite choices on almost every point. Its members were few, salaried by the crown, chosen by the state, and organised in ranks; it worked on problems the state wanted solved, and it published collectively. The English body was larger, unpaid, self-financed, open to anyone respectable who would pay a shilling a week, and correspondingly amateur. Both models still exist, and the difference between them is not a national quirk. A salaried academy can direct effort at a problem the state wants solved and can sustain a programme over decades, which is how French astronomy came to dominate the measurement of the earth. A subscription society cannot direct anything, and depends on whoever turns up, but it is much harder to silence, since no one can be dismissed from it for reaching an unwelcome result. Every arrangement for funding enquiry since has sat somewhere between the two, and has inherited the same trade.
The literary technology
The most easily missed invention is a way of writing.
Boyle's experimental reports are extraordinarily long-winded by any earlier standard, and the prolixity is the point. He describes the apparatus in detail sufficient to rebuild it, names the people present, gives the date, reports the trials that failed as well as those that worked, and hedges his conclusions with qualifications about what he did not establish. His books carry detailed engravings of the pump, which is not decoration but specification.
The historians Steven Shapin and Simon Schaffer named the effect virtual witnessing: the reader is put in the position of someone who was in the room, and a fact witnessed by a hundred readers is more solid than one witnessed by six fellows. Reporting failures is central to it. An account in which everything worked reads as a claim about the author's skill; an account including the trials that leaked and the seals that failed reads as a description of an object that behaves in a certain way, which is what an experimental fact is meant to be.
Around this sat a convention of civil dispute. Disagreement was to be about the fact and not the person, hypotheses about causes were to be kept separate from reports of what happened, and a fellow who could not reproduce a result was to say so plainly and without imputing dishonesty. Those conventions look like manners. They are the mechanism by which a contested claim can be argued to a conclusion instead of becoming a quarrel between gentlemen, which in that period could be settled with a sword.
Example. Boyle reports the trials in which his pump leaked and the experiment failed. Why does including them strengthen rather than weaken the report?
Because the reader's problem is not whether Boyle is clever but whether the phenomenon is real, and a report of unmixed success is compatible with a great many things other than a real phenomenon, including selective reporting and an author skilled at making an apparatus behave. Failures give the reader the information needed to distinguish those cases: they show the conditions under which the effect does not appear, which is how you learn what the effect depends on, and they show that the author is describing the machine's behaviour rather than curating an impression. There is a practical benefit too, which is that the next person to build a pump knows where the seals fail and does not conclude from a leak that Boyle was lying.
Now you. Hobbes objected that a fact produced by an expensive machine in a closed room, witnessed by a self-selected club, is no foundation for knowledge at all. Where is he right?
Answer
He is right on the narrow technical point and on part of the philosophical one. Boyle's pump did leak, badly, and Hobbes was correct that the receiver was never empty, which means the phenomena were being produced in rarefied air rather than in a void and every conclusion drawn about a vacuum was strictly unsupported. He is also right that a collection of facts has no logical force on its own: no number of reports about what a machine did entails a general truth about nature, and Hobbes, who wanted philosophy to be demonstrative like geometry, deriving consequences from definitions, was pointing at a genuine gap. Where he was wrong is in the conclusion that nothing could be built this way. What the experimentalists had that he lacked was a method for accumulation: many imperfect facts, produced by different machines in different hands, converging on the same relations, with the disagreements themselves becoming information about the apparatus. His deeper objection was political, that a body of gentlemen settling questions among themselves was setting up a rival authority to the sovereign, and about the sociology of it he was perfectly correct. That is precisely what the Royal Society was.
The journal
The final piece arrived on 6 March 1665, when Henry Oldenburg, the society's secretary, brought out the first issue of Philosophical Transactions, a private venture he edited and largely paid for and from which he hoped, unsuccessfully, to make a living. The Journal des Sçavans had appeared in Paris two months earlier with a broader remit.
Oldenburg's innovation is the combination of four things in one object. It appears on a date, so priority is fixed by a public record. It appears at intervals, so the reader has a reason to keep looking. It is a compilation, so the news of the whole network reaches someone who belongs to none of it. And its contents were vetted before printing, informally by Oldenburg and by fellows he consulted, which is the ancestor of refereeing, made a formal requirement when the society took the journal over in 1752.
The volume of work behind it is worth stating. Oldenburg conducted the society's foreign correspondence himself, in several languages, at a rate that reached tens of letters a week, and in 1667 he was imprisoned in the Tower of London for two months on suspicion of intelligence with the enemy during the Dutch war, because a man writing constantly to foreigners looked exactly like a spy. Philosophical Transactions has appeared continuously ever since, which makes it the longest-running scientific journal in the world.
Example. List what a fact had to acquire, by 1670, before it could outrank a text of Aristotle.
It had to be produced by an apparatus described in enough detail for someone else to build it. It had to be witnessed, by named people, on a stated date, and entered in a record the author did not control. It had to be reproduced, by other people using other instruments, with the failures reported too. It had to be published in a dated periodical that put it in front of readers who had no stake in the outcome. And it had to survive the objections of anyone who cared to make them, argued under conventions that made disagreement about the claim rather than about the man. Every one of those is a social arrangement rather than a discovery, and together they answer the question the first lesson posed. A text was preferred to an observation in 1500 because a text was stable, public and checkable while an observation was none of those things. By 1670 an observation could be all three.
Now you. Why does none of this machinery guarantee that the facts it certifies are true?
Answer
Because every part of it is a way of managing testimony and none of it touches nature directly. A phenomenon can be reproduced by twenty competent people and still be an artefact of an assumption they all share, which is exactly what happened to Tycho's measured stellar discs, described in an earlier lesson: careful, repeatable, agreed by everyone, and not a property of the stars. Refereeing filters for plausibility, which favours the consensus. Witnessing establishes that something appeared to happen in a room. What the machinery actually provides is not truth but correction: it makes claims public, attributable and testable, so that an error has a definite address and can be found by someone with a motive to find it. That is a weaker guarantee and a more useful one, and it is why the honest description of this method is not that it produces certainty but that it produces claims which can be shown to be wrong.
By 1670 there was an apparatus for producing and certifying knowledge about nature: instruments with known errors, a technique of contrived experiment, a mathematics adequate to describe motion, a mechanical picture of what explanations must look like, and institutions that made a result public and durable. What there was not was a physics. Nothing yet explained why Kepler's ellipses have the shape they do, and nothing connected the fall of a stone to the motion of the moon. The next lesson is about the calculation that did.