Posted September 20, 2004
There is a history of arguments which were used against one natural explanation of origins: Epigenesis, the development of the individual living thing. This history can shed light on the use of the same arguments against another natural explanation of origins: Evolution, which deals with populations of living things.
There are many sayings to remind us how rare it is to have a truly original idea. It is often startling to read through history and find that the latest fads are a repeat of something from long ago.
This was my experience when reading a book by Edwin Tenney Brewster, Creation: A History of Non-Evolutionary Theories.
Brewster discussed what we can call "scientific theories of creation", and one that got my attention involved the 18th century discussion of how an individual living thing came into its mature form. Did it develop from an unformed state or did it exist in some form in its precursor?
When does this creation occur?
...If there is no epigenesis but only [the "rolling out" of pre-formed organs], then there is no such thing as generation either. All creatures that ever were, or are now, or ever shall be to the end of time, must have been created at the beginning by the direct act of God, as germs.
[Brewster: Creation, page 166.]
For those who are unfamiliar with the issues, there is a summary Survey of the controversy below. Briefly: "Preformation", the idea that there was no real development, was a dominant scientific idea for about 200 years, centering on the 18th century. The "other side" of the controversy was represented by "Epigenesis".
Epigenesis caused some people discomfort, for it seemed incompatible with concepts of society and creation. And it is interesting to see how many of the arguments used in favor of Preformation have been recirculated (possibly unawares) as arguments against evolutionary biology. These arguments were not always what we would call "scientific": They could be philosophical, ethical, or theological.
The purpose of this essay is to look at a few of the issues which were brought up regarding Preformation and Epigenesis. The particularly scientific arguments and experiments were eventually resolved. But other objections persisted beyond their original application: they kept the substance of the objection and changed the thing objected to.
"Which came first, the chicken or the egg?" -- that old question seemed to be a problem for traditional Epigenesis, and might be asked about Evolution, today, by anti-Evolutionists. Quite literally: How could a chicken come from something which is not a chicken; and the early investigators (beginning with Aristotle) examined chicken eggs at various stages of growth. But it can also serve as a metaphor: Which came first, the objections or the objectionable idea? Here there are a few of these objections:
Since the publication of Behe: Darwin's Black Box, the expression "Irreducible Complexity" has received much notice within the anti-evolutionary community. A biological system is said to be Irreducibly Complex if it could not work as a system if a significant part of it were missing, and thus, supposedly, it could not develop in a gradual, evolutionary way.
Some 300 years ago, Nicolas Malebranche argued that there could not be an Epigenesis because of the interactions between the various organs in a complex living thing. A heart could not develop, he said, before there were veins to carry the blood, and the veins could not be there before there was a heart, and so on for the various organs of an animal.
The same argument against Epigenesis and for Preformation was also used by Cotton Mather, Charles Bonnet, and Abraham Trembley. See the quotions about Irreducible Complexity below.
Let us pause for a moment and reflect on what we can learn from the history of the idea of Irreducible Complexity, as seen through the eyes of the 18th century.
This could be repeated for other arguments from the era of Preformation (in particular for the arguments which will be looked at later) and perhaps also for arguments which, although as a matter of historical accident did not arise then, are current today.
I have chosen this argument because it is being used today as an argument against Evolution. It is not merely of historical interest. Perhaps history can shed light on the soundness of the argument in general, and in particular on how much it supports a different conclusion from its earlier use. Insofar as we can use the word "creationism" to describe ideas before the word was used, Preformation was a scientific theory of creationism.
Next, because the argument, as used to argue against Epigenesis, was at least as sound as its present use against Evolution. Perhaps it was more sound, because it was not merely against Epigenesis, it was for Preformation. (As distinguished from being merely against Evolution, with it being left open as to what it is for.) And it was part of a consilience of evidence for this genuinely scientific theory, which included observational examinations.
Finally, because this argument was used in its earlier form in the debate about the origins of individuals, rather than the origins of species, kinds, types, patterns, generalities or abstractions. This shows that this distinction, between "origins of individuals" and "origins of kinds", is not merely metaphysical hair-splitting, but is a distinction which makes a difference in the real world. This is not a "straw man". The argument was used by serious, intelligent, informed people in support of a legitimate scientific investigation. We can use this distinction as a tool to examine other arguments, asking the question: "Is this an argument against Evolution, or is it more properly an argument against Epigenesis?"
These further examples suggest that there is a pattern to this history of arguments.
Many people are concerned that evolutionary biology has troublesome conflicts with traditional Christian theology, especially with the concept of Original Sin. It is interesting that this particular theological problem has also been anticipated in the Epigenesis:Preformation debate.
There are some scattered allusions in the Bible which have been taken as support for the idea of pre-existence of the body in one's ancestors (Genesis 25:23, and Jeremiah 1:15 for existence in the maternal body); but the one that has received the most attention, as far as Original Sin and Preformation, was Hebrews 7:10.
Jan Swammerdam made the explicit association between Original Sin and Preformation, although hints of it are given by James Ussher and back to Augustine. Extended quotations about Original Sin are given below.
Although Voltaire was not a systematic scientist and was certainly not a traditional Christian believer, he did accept the idea of Preformation, in part because of his deistic beliefs, and used the power of his rhetoric to argue against Spontaneous Generation especially. It is interesting to see that this person -- perhaps the epitome of the anti-church deist of the 18th century -- argued vehemently for Preformation, using several of the same arguments that feel comfortable to modern religious anti-evolutionists.
The copious writings of Voltaire make for a handy source for a longer list of further objections to Epigenesis. These objections may have been used by others, and may have not all been original with him.
Here are a few of his themes:
One of the more famous quotations of Voltaire is "If God did not exist, we would have to invent Him" "Épitre à l'auteur du livre des Trois imposteurs"-- meaning, for Voltaire, that morality is possible only for those who believe in God. Moreover, Voltaire often claimed that Spontaneous Generation and Epigenesis led to atheism:
If animals were born without a germ, there would be no more cause of generations; a man could just as easily be born of a lump of earth as an eel from a bit of paste. This ridiculous system would obviously lead others to atheism.[Avertissement to Letters 5-8]
[my translation]
See also Voltaire's essay on "Atheism" in his Philosophical Dictionary.
The analogy between a watch and a living thing, the watch being so complicated that it requires a watchmaker, so too a living thing requires a designer. In the 18th century, the issue was about each individual living thing being a creature; in the 21st century the individuals have been forgotten, and the issue is rather "kinds" of living things.
... no matter what some savants say nowadays, one can be a very good philosopher and believe in God. The atheists never replied to the difficulty that a clock proves a clock-maker.[To Marquis Villevielle]
[my translation]
Later, in this same letter, he brings up a little calculation of the small probability of getting the opening of Virgil's Aeneid by throwing letters at random, and adds the comment that "Two Aeneids together do not make a third."
The expression Spontaneous Generation naturally suggests the thought that the living thing "just happens", and Voltaire, like 21st century anti-evolutionists, identifies anything other than creation as being "chance".
Voltaire has a long essay in his Philosophical Dictionary defending the concept of Final Causes. See "Final Causes"
Voltaire seems to have had a limited concept of what sciences could investigate, rather similar to 21st century objections to Evolution as not a "true science":
True physics consists then in the proper determination of all the facts. We will know first causes when we are gods. It is given to us to calculate, to weigh, to measure, to observe; this is natural philosophy; almost all the rest is a chimera.["Cartesianisme"]
[my translation]
When reading authors from the 18th century or thereabouts, keep in mind that there can be a shift in the meaning of words over time.
When they are talking about "design", they might mean one thing while a 21st century writer means another. For one thing, remember that in earlier days, the typical human designer would have been the craftsman or artisan who would make objects individually, whereas today, the designer is someone who draws up designs for mass production or even for a system for producing designs. The 18th-century problem that we are looking at is a problem about how each individual living organism comes to be and whether it was individually designed or grew on its own. The 21st-century complaint about evolution is that it displaces not individual creation, but wholesale design of species or kinds of living things. When the 18th century philosopher contemplated the complexity of an eye and couldn't imagine how an eye could arise by natural processes apart from a designer, it was an eye that was being talked about, not -- as is regularly the case today -- the eye. That is, each individual eye, one at a time, rather than the overall pattern of all eyes.
There are, of course, other arguments proposed today against evolutionary biology. It is far beyond the scope of this essay to cover those which are new, but perhaps we can suggest that an interested reader could try this exercise: How many arguments which are brought up against evolutionary biology might be at least as appropriate as an argument against Epigenesis?
This suggests a minor research problem in the history of thought: How many 21st century arguments against Evolution were anticipated in the 18th century as arguments against Epigenesis? Can an argument against Evolution be identified which has no precursor in the anti-Epigenesis debate?
There is one major difference in the old anti-Epigenesis arguments, though, and that is that there was a positive alternative theory available -- Preformation offered a description and explanation of what happened, and there were experimental investigations proposed, and actually done, in support of Preformation. Preformation was a genuine theory, and a scientific theory.
This essay suggests some of the range of those who objected to Epigenesis at least in part for theological or philosophical reasons. And some of these objections have persisted, even though the original issue has faded away, and was replaced by the new issue of evolution.
In summary, then:
Short expositions of one phase of Voltaire's campaign against
Spontaneous Generation are in
Hellman: Voltaire versus Needham
Roe: Voltaire vs. Needham
How does the complexity of structures of each living thing arise? There is a confusing complexity of different terms used in the literature. As is far too common, people attempt to coin new words to make fine distinctions, only to have the words used in different ways by different authors. See comments about the variety of expressions in Strick: Sparks of Life, especially pages 11-12, 90-91, 237. I will restrict this to just three technical terms, "Epigenesis", "Spontaneous Generation", and "Preformation".
The first, ancient answer to the central question -- going back at least as far as Aristotle -- is to accept the common-sense observation that these complexities do develop from basically unformed predecessors, for example, plants from seeds and egg-laying animals from eggs. The modern-day equivalent of this is essentially developmental biology, the study of how all of the varieties of cell-types and organs in the adult come from a single precursor cell (the fertilized egg, for example).
Closely associated with Epigenesis is the idea that living things can develop from foreign material -- as mistletoe grows on trees, flies from rotten flesh, mice in rubbish-heaps, and, indeed, butterflies (winged, six-legged insects) from caterpillars (non-flying, many-legged "worms"). This, of course, is also an ancient belief, going back at least as far as Aristotle. Today, in retrospect, we can recognize that Epigenesis and Spontaneous Generation can be distinguished. But in the 18th century, they were treated as a package by all sides of the dispute.
The new idea of the 17th century was that the basic structures of each living thing already existed in their complexity in their precursors, that is, the seed, eggs, or the newly-discovered spermatozoa. This is "preformation". Preformation began to get notice in the 17th century and seems to have been the dominant opinion of the 18th century.
An extension of preformation is "pre-existence": That not merely the major organs exist in the precursor to the mature form, but that the entire mature body actually exists, in a small form, in the precursor, and that what we perceive as development is merely growing larger.
An extreme form of preformation held that, as the egg contained the adult form, and the adult form contained eggs, there was a nesting, as the common metaphor puts it, like Russian dolls; so that all generations of humans were contained within the body of Eve. In partial defense of this idea, which is a subject of ridicule today, remember that Newtonian physics and infinitesimal calculus presumed that matter was infinitely divisible and that there was no idea that there was a lower limit, imposed by the size of cells, to the size of a living thing. Microscopes had discovered an amazing variety of unsuspected complex small life. At this point a quotation from Swift's "On Poetry" of 1733 is usually demanded:
So, Nat'ralists observe, a Flea
Hath smaller Fleas that on him prey,
And these have smaller yet to bite 'em,
And so proceed ad infinitum:
Today, the typical references one can find to Preformation tend to be dismissive, even ridiculing it with the idea of a "little man" inside the mother (or father). Today, so it goes, we all know better, that there really is a process of development from a fertilized egg, and all of those people must have been sorely deluded to contemplate such a preposterous idea of an infinite sequence of "little men" inside one another, back to Eve (or Adam), and forward all generations.
Keep in mind that very little was known about such basic facts about the world of life, facts that we learn in elementary school, such as: all life is composed of cells and all life is based on chemistry; the mammalian egg had not yet been observed and microscopy was at a very primitive stage compared with even late 19th-century practice.
And just to hint at the complexity of the intellectual currents of the time, anything associated with Aristotle was in disfavor among many of the scientists of this era.
The idea of Preformation faded away in the early 19th century, although as late as the 1840s William Whewell could say that "It has always had many adherents; and has been, perhaps, up to the present time, the most current opinion on the subject of generation." [Philosophy of the Inductive Sciences, volume 1, page 295]. Spontaneous Generation gradually became dissociated from the "victorious" Epigenesis and was eventually discredited.
This essay is not the place (and I do not claim to be the person) for a history of biology during the Englightenment (roughly, that is, 18th century European culture). Rather, we are trying to find lessons from fragments of old debates for thinking about modern issues. In particular, it would take us far astray to consider what the supporters of Epigenesis had to say (and they were not silent).
Likewise, we are not concerned with what later theories of evolution had to say: Although this essay dwells on the issues of the origins of individuals and the origins of kinds -- what we can label "Ontogeny" and "Phylogeny" -- the essay is based on the differences between these concepts, not on any connection (such as the idea of "recapitulation", which came to prominence in a later period).
It must be stressed that this essay is not a "Whiggish history" which attempts to evaluate the past by present standards. But that does not preclude the evaluation of the present by present standards, including standards which are informed by our knowledge of the past.
An organized body contains an infinity of parts which mutually depend, one on the other, according to particular ends, & which must all be concurrently formed in order to act all together. Because it should not be thought, as did Aristotle, that the heart is the first one alive & the last dying. The heart cannot beat without the influence of the animal spirits, which spread themselves in the heart without the nerves, & the nerves draw their origin from the brain whence they receive the spirits. Moreover, the heart cannot beat & push blood in the arteries if they are not already made, as well as the veins which bring it back. In a word, it is obvious that a machine cannot act that is not completed, & that thus the heart cannot live alone.[Malebranche De la recherche]
[Book VI. Part II. Chapter IV.; volume 3 pages 169-170]
[my translation]
[See Aristotle "On Youth" 3: 468b28]
The question is thus to know, if an Animal, before it is perceptible, is already formed, if it has all its Organs, & if it has them since the first moment of its existence; or, if, in this state of smallness, the Organs are formed successively, & are not all formed & arranged, in this harmony which is between them, when the Animal becomes perceptible. In fact direct observations can be useful to clarify this question, since the small Animal is imperceptible in the circumstances in which it all is. But we can reflect on the observations made on the small Animals, when they became perceptible, & when they acquired considerable degrees of increase. We see whereas they form a whole composed of a multitude of parts closely plain between them; & that, to speak with the excellent Author, most properly to be used by us as Guide in this research, "all these parts of an Animal have between them such direct correspondences, so varied, so multiple, so close in connection, so indissoluble, that they must always have coexisted. The Arteries suppose the Veins: these & others suppose the Nerves; those the Brain; this last the Heart; & all suppose a multitude of Bodies."[Trembley Discours XVIII,volume I pages 263-264]
[my translation]
[the "excellent Author" is cited is Bonnet, volume 1, page 154]
[see Wesley vol. 2, page 238]
There is nothing in the Animal Machine, but an inconceivable number of branching and winding Canals, filled with Liquors of different Natures, going a perpetual round, and no more capable of producing the wonder Fabrick of another Animal, than a thing is of making itself. There is besides in the Generation of an Animal, a necessity that the Head, Heart, Nerves, Veins and Arteries, be formed at the same time, which never can be done by the motion of any Fluid, which way soever moved.
[Cotton Mather, Essay XXVI. "Of Insects"; reprint, page 154]
Now, there is no doubt that God knew Jeremiah before He formed him in the womb, for He says quite clearly, Before I formed you in the womb, I knew you. But it is difficult, if not impossible, for our limited understanding to know where God knew him before forming him. Was it in some proximate causes, as in the case of Levi, who paid tithes when he was in the loins of Abraham? Was it in Adam himself, in whom the whole human race had its roots? And if in Adam, was it when he had been formed from the slime, or was it when he had been made in his causes in the works which God created simultaneously?[Augustine, Book 6 Chapter 9 Paragraph 14, pages 187-188]
Secondly, that we all who are descended from Adam by naturall generation, were in his loyns and a part of him when he fell, and so by the law of propagation and generation sinned in him, and in him deserved eternall condemnation; therefore as two Nations are said to be in the womb of Rebekah, Gen.25.23 and Levi to have paid tithes to Melchisedec in the loins of Abraham, Heb.7.9,10. who was not born some hundred years after, so is it here.
[Ussher, Head 9, "Of Originall and Actuall sinne ...", page 142]
Moreover, the reason is evident, how Levi, being yet in his father's loins, paid tythes long before he was born: for he was in his father's loins, when Melchisedek met Abraham. Lastly, even original sin (in the opinion of a very learned man, to whom we have occasionally communicated the mysteries of our experiments) may stand on this principle as on a firm foundation, since all mankind have been laid up originally in the loins of their first parents.[Swammerdam, Part I Chapter III, page 16]