The dry, clear style of writing (which we would now call ‘factual’) that defined the new philosophy is especially remarkable in Huygens’s description of the third experiment in his notebook: “Een cijsje in de fles geset. De eerste en tweede treck scheen noch niet seer geincommodeert. Daer nae begost te hijghen. Dae nae sijn hooft te laten hangen en met sijn oogen te knicken. Daer nae wierdt noch eens heel wacker en sloegh met sijn vleugels, maer sat haest weer stil en viel voort van sijn selven en doot. Ieder treck saghmen dat het wat swol. [Put a siskin in the flask. The first and second pull it did not seem too hampered. Then, it started panting. Then, it hung its head and blinked its eyes. Then, it woke up once more and beat its wings, but sat soon still again and fell down, dead. With each pull, one could see it swell a bit.]”
Doing experiments with living animals, even cutting them open to see how they ‘worked’ (‘vivisection’) was a common practice during the 17th century. One prominent view on animals was that of the ‘beast-machine’, which compared animals to clocks, as automata without a soul and without the ability to suffer. Huygens himself was not very convinced by the beast-machine metaphor. According to him, the fact that animals cried and ran away from sticks was plain evidence that the comparison of animals to clocks was absurd and cruel. This view is, however, not apparent from the unemotional, mechanistic description of his experiment with a bird. So although moral questions about the practice of vivisection were raised, the laboratorium of the experimental community seemed to have been protected from them. All that was not, and could not be, a matter of fact, was not allowed to enter. The borders of the fact-factory needed to be defended strictly against the metaphysical speculation and prejudices it was supposed to end.
As we are now convinced that animals can indeed suffer and as ethical committees govern the use of animals in scientific experiments, we were not able to replicate this specific experiment. We will have to take Huygens’s description for granted. Instead, we re-enacted an experiment Huygens set up after noticing the following in the aftermath of his experience with the bird: “De lucht soo veel als moghelijck uijtgepompt sijnde maeckten ick dat een licht veertien van ’t dode vogeltie van boven in de fles, nederwaert viel: en viel soo ras neer als een stuck loot daer het in de lucht wel 2 of 3 seconden onderwegh soude geweest sijn. [After having pumped out the air as much as possible, I noticed how a small feather from the dead bird at the top of the receiver fell down: and it fell as quickly as a piece of lead, whereas in the air it would have taken 2 or 3 seconds.]”
Every now and then, however, the laboratorium could not be protected against the intrusion of the world outside. As will be shown by next experiment, facts don’t always speak for themselves, and with their interpretation comes speculation and discussion, causing the factory of facts to shake on its foundations.