The Amazing Redi

[Oecolampadius]

It was once believed that maggots were spontaneously generated from rotting meat. Francesco Redi, however, believed that the source of the maggots was the eggs and tiny larvae deposited on the meat by flies. Because “belief would be vain without the confirmation of experiment,” he set up a way to test his hypothesis. He put meat in two jars, one uncovered that flies could enter, another covered with fine mesh cloth that would keep the flies out. He observed that the meat in the open jar became infested with maggots, while the meat in the covered jar remained free of maggots, although flies landed on the cloth cover, some actually observed depositing tiny larvae. I've posted a poll to get your take on his experiment.

 

[Keith&Co.]

Whoops. Wrong button. I meant B, hit C.

 

[Peez]

Since it is possible that the Invisible Pink Unicorn manipulated the results, these results do not prove anything. I think you should start by proving that objective reality exists, from there perhaps one could start to address proofs of the possible nature of that alleged reality.

Peez

 

[KeepTalking]

I voted B, but on further reflection I could have just as easily voted D (both A and B). Redi first disproved the prevailing concept of spontaneous generation, then observed that his theory that the flies reproduced using eggs and larvae was correct.

 

[lpetrich]

I recall that he started getting skeptical about spontaneous generation when he noticed that rotting meat attracts the same kinds of flies that it seemingly produces. He also discovered that dead flies do not make new flies, but that live ones do. He wrote about his work in 1668, and what he described is still a classic in experimental design.

However, he did not completely reject spontaneous generation. He believed that galls on plants make gall midges. Flies from meat and wasps from trees: Reevaluating Francesco Redi's spontaneous generation experiments. - PubMed - NCBI discusses his work there. Seems like he didn't catch gall midges laying eggs on plants. When a larva hatches, it burrows in and makes the plant tissue around it grow into a gall.

 

[lpetrich]

Around 1620, alchemist Jan-Baptista van Helmont published this recipe for mice:

... for if you press a piece of underwear soiled with sweat together with some wheat in an open mouth jar, after about 21 days the odor changes and the ferment coming out of the underwear and penetrating through the husks of the wheat, changes the wheat into mice. But what is more remarkable is that mice of both sexes emerge (from the wheat) and these mice successfully reproduce with mice born naturally from parents? But what is even more remarkable is that the mice which came out were not small mice? but fully grown.

What should he have done with that jar?

But some of his colleagues were starting to get skeptical.

Concerning the generation of Froggs, we shall briefly deliver that account which observation hath taught us. By Frogges I understand not such as arising from putrefaction, are bred ....but they let fall their spawn in the water... In this spawn of a lentous and transparent body, are to be discerned many specks, or little conglobulations, which in a small time become of deep black.... Now of this black or duskie substance is the Frogge at least formed; as we have beheld, including the spawn with water in a glass, and exposing it unto the Sun. For that black and round substance, in a few days began to dilate and grow longer, after a while the head, the eyes, the tail to be discernable, and at last to become that which the Ancients called Gyrinus, we a Porwigle or Tadpole. This in some weeks after becomes a perfect Frogg, the legs growing out before, and the tail wearing away, to supply the other behind.

Sir Thomas Browne, Pseudodoxia Epidemica, 1672 6th edition

He also expressed skepticism about the spontaneous generation of mice (Pseudodoxia Epidemica, Bk 3, Ch 28). He got this response:

So we may doubt whether in cheese and timbers worms are generated, or if beetles and wasps in cow-dung, or if butterflies, locusts, shell-fish, snail, eels, and such life be procreated of putrefied matter, which is to receive the form of that creature to which it is by formative power disposed. To question this is to question reason, sense, and experience. If he doubts this, let him go to Egypt, and there he will find the fields swarming with mice begot of the mud of the Nylus, to the great calamity of the inhabitants.

Alexander Ross, Arcana Microcosmi, Bk 2, Ch 10, pp 151-156, 1652

 

[lpetrich]

Francesco Redi also noted that when one keeps flies away with rotting meat with gauze, that some flies lay eggs on the gauze.

Also, on spontaneous generation, belief in it was not an all-or-nothing thing. "Large" organisms were generally not believed to be spontaneously generated, while "small" organisms generally were. Francesco Redi's experiments were a clear counterexample for some "small" organisms, and it forced the dividing line downwards. In the 18th century, it was commonly believed that many microorganisms were spontaneously generated, but that notion also was gradually refuted.

Modern conceptions of the origin of life are more-or-less a revival of spontaneous generation, but spontaneous generation in special circumstances and producing very primitive organisms. Nothing like Van Helmont's mouse recipe.

 

[Oecolampadius]

However, he did not completely reject spontaneous generation. He believed that galls on plants make gall midges. Flies from meat and wasps from trees: Reevaluating Francesco Redi's spontaneous generation experiments. - PubMed - NCBI discusses his work there. Seems like he didn't catch gall midges laying eggs on plants. When a larva hatches, it burrows in and makes the plant tissue around it grow into a gall.

Although he screwed up with the gall midge business, his mistake involved believing that living plants could generate other living organisms such as gall midges. His fly experiments, however, dealt with whether dead tissue could generate living organisms, and he was right on point.

 

[Oecolampadius]

Here's Redi himself on proving stuff (p. 37 of Bigelow's 1909 translation of Experiments on the Generation of Insects, easily available online):

"It is true that some kinds of flies bring forth live worms and others eggs, as I have proved by experiment." (Emphasis added.)

 

[Kharakov]

Did prove by experiment mean observe back then?

I proved by experiment that an SUV just drove past the window. I am proving a little tiny fly is walking on my laptop's power cord, which I also proved. I am no longer proving that a little tiny fly is walking on my laptop's power cord. Given my insanity and penchant for hallucination, I'm not sure about the fly existing, but I definitely proved it.

 

[Oecolampadius]

Did prove by experiment mean observe back then?

He set up an apparatus that drew the flies to the meat but kept them off the meat, said apparatus also enabling him to see that the flies laid eggs and live larvae. Apparently the eggs and live larvae could be seen when deposited on the fine mesh of the apparatus but not when deposited on unprotected meat.

 

[bilby]

Did prove by experiment mean observe back then?

I proved by experiment that an SUV just drove past the window. I am proving a little tiny fly is walking on my laptop's power cord, which I also proved. I am no longer proving that a little tiny fly is walking on my laptop's power cord. Given my insanity and penchant for hallucination, I'm not sure about the fly existing, but I definitely proved it.

The word 'prove' meant 'test'; The modern meaning of 'show beyond doubt to be true' is quite recent, supplanting the earlier meaning somewhere between the two World Wars.

Try reading it as: "It is true that some kinds of flies bring forth live worms and others eggs, as I have tested experimentally", or the less clunky: "My experiments have found that some kinds of flies bring forth live worms, and others eggs", to get an accurate modern translation.

Compare such phrases as 'The proof of the pudding is in the eating' - which means that eating the pudding is the only worthwhile test of its quality. Clearly it makes no sense to try to eat a pudding whose existence has not yet been proven.

The past is a foreign country, and a wise tourist learns the local language before setting out.

 

[Oecolampadius]

The modern meaning of 'show beyond doubt to be true' is quite recent, supplanting the earlier meaning somewhere between the two World Wars.

The second definition of "prove" found in the 1895 edition of Webster's International Dictionary:

To evince, establish, or ascertain, as truth, reality, or fact, by argument, testimony, or other evidence.

 

[bilby]

The modern meaning of 'show beyond doubt to be true' is quite recent, supplanting the earlier meaning somewhere between the two World Wars.

The second definition of "prove" found in the 1895 edition of Webster's International Dictionary:

To evince, establish, or ascertain, as truth, reality, or fact, by argument, testimony, or other evidence.

Indeed. Whereas a newer edition would have that as the first definition, and a concise modern dictionary might well have only that definition.

 

[Oecolampadius]

The second definition of "prove" found in the 1895 edition of Webster's International Dictionary:

To evince, establish, or ascertain, as truth, reality, or fact, by argument, testimony, or other evidence.

Indeed. Whereas a newer edition would have that as the first definition, and a concise modern dictionary might well have only that definition.

But that's not the point. You seemed to insinuate that the "modern" usage of "prove" wasn't available to someone translating Redi in 1909, but I proved (i.e., established as fact) that it was available by finding a dictionary definition of such dating from 1895.

Back in the day, armorers would "prove" their armor by popping a pistol ball on a steel breastplate to see if the steel would withstand penetration. That is where the word "bulletproof" comes from. This, along with such actions tasting pudding to make sure the batch came out right, carries the connotation of simple, empirical quality control tests.

Redi, however, was not performing a simple quality control test but instead was designing a rather sophisticated experiment to challenge the conventional wisdom that maggots were spontaneously generated from rotting meat.

Let's substitute "ascertained as fact" for "proved" in the cited quote and see what we get:

"It is true that some kinds of flies bring forth live worms and others eggs, as I have ascertained as fact by experiment."

By the way, the translator, Robert Payne Bigelow, was himself a trained scientist who was teaching biology at MIT at the time he made his translation.

 

[bilby]

Indeed. Whereas a newer edition would have that as the first definition, and a concise modern dictionary might well have only that definition.

But that's not the point. You seemed to insinuate that the "modern" usage of "prove" wasn't available to someone translating Redi in 1909, but I proved (i.e., established as fact) that it was available by finding a dictionary definition of such dating from 1895.

You might misinterpret what I said in that way, but that's not what I said, nor is it what I meant. The modern usage of 'prove' wasn't the most commonly intended meaning in 1909. Whether the misunderstanding was 'available' to be made then is irrelevant; a reader in 1909 would have started from the assumption that he was using 'prove' in the fashion most common at the time.

 

[Oecolampadius]

Only One Thin Dime ! ! !

Ladies and gentlemen, hurry, hurry, hurry! Step right up and see the amazing Hermeneutical Houdini attempt to escape from the dreaded semantic straightjacket right before your very eyes!