Precambrian rabbit
Encyclopedia
At one time, "Precambrian
rabbit
s" or "fossil
rabbits in the Precambrian" rock samples became popular image
ry in debates about the validity of the theory of evolution and the scientific field of evolutionary biology. The images are reported to have been among responses given by the biologist, J.B.S. Haldane, when he was asked what evidence
could destroy his confidence in the theory and the field of study. Many of his statements about his scientific research were popularized in his lifetime.
Some accounts use this response to rebut claims that the theory
of evolution is not falsifiable by any empirical evidence. This followed an assertion by philosopher, Karl Popper
, who had proposed that falsifiability is an essential feature of a scientific theory. Popper also expressed doubts about the scientific status of evolutionary theory, although he later concluded that the field of study was genuinely scientific.
Rabbits are mammals. From the perspective of the philosophy of science
, it is doubtful whether the genuine discovery of mammal
ian fossils in Precambrian rocks would overthrow the theory of evolution instantly, although, if authentic, such a discovery would indicate serious errors in modern understanding about the evolutionary process. Mammals are a class of animals, whose emergence in the geologic timescale is dated to much later than any found in Precambrian strata. Geological records indicate that although the first true mammals appeared in the Triassic
period, modern mammalian orders appeared in the Palaeocene and Eocene
epochs of the Palaeogene period. Hundreds of millions of years separate this period from the Precambrian.
rabbit
in Precambrian
rocks would be enough to destroy his belief in evolution
. However these references date from the 1990s or later. In 1996 Michael J. Benton
cited the 1993 edition of Mark Ridley
's book Evolution, Richard Dawkins
wrote in 2005 that Haldane was responding to a challenge by a "Popperian
zealot". In 2004 Richa Arora wrote that the story was told by John Maynard Smith
(1920–2004) in a television programme.
held that any scientific proposition must be falsifiable
, in other words it must at least be possible to imagine an experiment
whose outcome would disprove the hypothesis. Initially he thought that Charles Darwin
's theory of natural selection
(often summarized as "the survival of the fittest") was untestable in this sense, and therefore "almost tautological
." Popper later changed his view, concluding that the theory of natural selection is falsifiable and that Darwin's own example of the peacock's tail had disproved one extreme variation of it, that all evolution is driven by natural selection. Although in 1978 Popper wrote that his earlier objection had been specifically to the theory of natural selection, in lectures and articles from 1949 to 1974 he had stated that "Darwinism" or "Darwin's theory of evolution" was a "metaphysical research programme" because it was not falsifiable. In fact he continued to express dissatisfaction with contemporary statements of the theory of evolution which focused on population genetics, the study of the relative frequencies of allele
s (different forms of the same gene
). Unfortunately some of the adjustments he proposed resembled Lamarckianism or saltationism, evolutionary theories that were and still are considered obsolete, and evolutionary biologists therefore disregarded his criticisms. In 1981 Popper complained that he had been misinterpreted as saying that "historical sciences" such as paleontology
or the history of evolution of life on Earth
were not genuine sciences, when in fact he believed they could make falsifiable predictions.
Further confusion arose in 1980–1981, when there was a long debate in the pages of Nature
about the scientific status of the theory of evolution. None of the parties seriously doubted that the theory was both scientific and, according to current scientific knowledge, true. Some participants objected to statements that appeared to present the theory of evolution as an absolute scientific dogma, however, rather than as a hypothesis that so far has performed very well, and both sides quoted Popper in support of their positions. Some Creationists took this as an opportunity to declare that the theory of evolution was unscientific.
said that the discovery of fossil mammals in Precambrian rocks would "completely blow evolution out of the water." Philosopher Peter Godfrey-Smith
doubted that a single set of anachronistic fossils, however, even rabbits in the Precambrian, would disprove the theory of evolution outright. The first question raised by the assertion of such a discovery would be whether the alleged "Precambrian rabbits" really were fossilized rabbits. Alternative interpretations might include incorrect identification of the "fossils", incorrect dating of the rocks, and a hoax
such as the Piltdown Man
was shown to be. Even if the "Precambrian rabbits" turned out to be genuine, they would not instantly refute the theory of evolution, because that theory is a large package of ideas, including: that life on Earth has evolved over billions of years; that this evolution is driven by certain mechanisms; and that these mechanisms have produced a specific "family tree" that defines the relationships among species and the order in which they appeared. Hence, "Precambrian rabbits" would prove that there were one or more serious errors somewhere in this package, and the next task would be to identify the error(s).
Benton pointed out that, in the short term, scientists often have to accept the existence of competing hypotheses, each of which explains large parts—but not all—of the observed relevant data.
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
rabbit
Rabbit
Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...
s" or "fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
rabbits in the Precambrian" rock samples became popular image
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
ry in debates about the validity of the theory of evolution and the scientific field of evolutionary biology. The images are reported to have been among responses given by the biologist, J.B.S. Haldane, when he was asked what evidence
Evidence
Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either presumed to be true, or were themselves proven via evidence, to demonstrate an assertion's truth...
could destroy his confidence in the theory and the field of study. Many of his statements about his scientific research were popularized in his lifetime.
Some accounts use this response to rebut claims that the theory
Theory
The English word theory was derived from a technical term in Ancient Greek philosophy. The word theoria, , meant "a looking at, viewing, beholding", and referring to contemplation or speculation, as opposed to action...
of evolution is not falsifiable by any empirical evidence. This followed an assertion by philosopher, Karl Popper
Karl Popper
Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...
, who had proposed that falsifiability is an essential feature of a scientific theory. Popper also expressed doubts about the scientific status of evolutionary theory, although he later concluded that the field of study was genuinely scientific.
Rabbits are mammals. From the perspective of the philosophy of science
Philosophy of science
The philosophy of science is concerned with the assumptions, foundations, methods and implications of science. It is also concerned with the use and merit of science and sometimes overlaps metaphysics and epistemology by exploring whether scientific results are actually a study of truth...
, it is doubtful whether the genuine discovery of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
ian fossils in Precambrian rocks would overthrow the theory of evolution instantly, although, if authentic, such a discovery would indicate serious errors in modern understanding about the evolutionary process. Mammals are a class of animals, whose emergence in the geologic timescale is dated to much later than any found in Precambrian strata. Geological records indicate that although the first true mammals appeared in the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
period, modern mammalian orders appeared in the Palaeocene and Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
epochs of the Palaeogene period. Hundreds of millions of years separate this period from the Precambrian.
Origin of the phrase
Several authors have written that J.B.S. Haldane (1892–1964) said that the discovery of a fossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
rabbit
Rabbit
Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...
in Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
rocks would be enough to destroy his belief in evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
. However these references date from the 1990s or later. In 1996 Michael J. Benton
Michael J. Benton
Michael J. Benton is a British paleontologist, a Fellow of the Royal Society of Edinburgh, and professor of vertebrate palaeontology in the Department of Earth Sciences at the University of Bristol....
cited the 1993 edition of Mark Ridley
Mark Ridley (zoologist)
Mark Ridley is a British zoologist and writer on evolution.He studied at both Oxford and Cambridge in the 1980s , was a professor at Emory University, Atlanta, U.S.A., and - as of 2005 - works at the Department of Zoology, Oxford University...
's book Evolution, Richard Dawkins
Richard Dawkins
Clinton Richard Dawkins, FRS, FRSL , known as Richard Dawkins, is a British ethologist, evolutionary biologist and author...
wrote in 2005 that Haldane was responding to a challenge by a "Popperian
Karl Popper
Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...
zealot". In 2004 Richa Arora wrote that the story was told by John Maynard Smith
John Maynard Smith
John Maynard Smith,His surname was Maynard Smith, not Smith, nor was it hyphenated. F.R.S. was a British theoretical evolutionary biologist and geneticist. Originally an aeronautical engineer during the Second World War, he took a second degree in genetics under the well-known biologist J.B.S....
(1920–2004) in a television programme.
Theoretical background
The philosopher Karl PopperKarl Popper
Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...
held that any scientific proposition must be falsifiable
Falsifiability
Falsifiability or refutability of an assertion, hypothesis or theory is the logical possibility that it can be contradicted by an observation or the outcome of a physical experiment...
, in other words it must at least be possible to imagine an experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
whose outcome would disprove the hypothesis. Initially he thought that Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
's theory of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
(often summarized as "the survival of the fittest") was untestable in this sense, and therefore "almost tautological
Tautology (logic)
In logic, a tautology is a formula which is true in every possible interpretation. Philosopher Ludwig Wittgenstein first applied the term to redundancies of propositional logic in 1921; it had been used earlier to refer to rhetorical tautologies, and continues to be used in that alternate sense...
." Popper later changed his view, concluding that the theory of natural selection is falsifiable and that Darwin's own example of the peacock's tail had disproved one extreme variation of it, that all evolution is driven by natural selection. Although in 1978 Popper wrote that his earlier objection had been specifically to the theory of natural selection, in lectures and articles from 1949 to 1974 he had stated that "Darwinism" or "Darwin's theory of evolution" was a "metaphysical research programme" because it was not falsifiable. In fact he continued to express dissatisfaction with contemporary statements of the theory of evolution which focused on population genetics, the study of the relative frequencies of allele
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
s (different forms of the same gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
). Unfortunately some of the adjustments he proposed resembled Lamarckianism or saltationism, evolutionary theories that were and still are considered obsolete, and evolutionary biologists therefore disregarded his criticisms. In 1981 Popper complained that he had been misinterpreted as saying that "historical sciences" such as paleontology
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
or the history of evolution of life on Earth
Evolutionary history of life
The evolutionary history of life on Earth traces the processes by which living and fossil organisms have evolved since life on Earth first originated until the present day. Earth formed about 4.5 Ga and life appeared on its surface within one billion years...
were not genuine sciences, when in fact he believed they could make falsifiable predictions.
Further confusion arose in 1980–1981, when there was a long debate in the pages of Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
about the scientific status of the theory of evolution. None of the parties seriously doubted that the theory was both scientific and, according to current scientific knowledge, true. Some participants objected to statements that appeared to present the theory of evolution as an absolute scientific dogma, however, rather than as a hypothesis that so far has performed very well, and both sides quoted Popper in support of their positions. Some Creationists took this as an opportunity to declare that the theory of evolution was unscientific.
Would anachronistic fossils disprove evolution?
Evolutionary biologist Richard DawkinsRichard Dawkins
Clinton Richard Dawkins, FRS, FRSL , known as Richard Dawkins, is a British ethologist, evolutionary biologist and author...
said that the discovery of fossil mammals in Precambrian rocks would "completely blow evolution out of the water." Philosopher Peter Godfrey-Smith
Peter Godfrey-Smith
Peter Godfrey-Smith is a professor of philosophy at Harvard University. Born in Australia in 1965, he received a Ph.D. in philosophy from UCSD in 1991, and joined Harvard in 2006 after previous positions at Stanford University and Australian National University...
doubted that a single set of anachronistic fossils, however, even rabbits in the Precambrian, would disprove the theory of evolution outright. The first question raised by the assertion of such a discovery would be whether the alleged "Precambrian rabbits" really were fossilized rabbits. Alternative interpretations might include incorrect identification of the "fossils", incorrect dating of the rocks, and a hoax
Hoax
A hoax is a deliberately fabricated falsehood made to masquerade as truth. It is distinguishable from errors in observation or judgment, or rumors, urban legends, pseudosciences or April Fools' Day events that are passed along in good faith by believers or as jokes.-Definition:The British...
such as the Piltdown Man
Piltdown Man
The Piltdown Man was a hoax in which bone fragments were presented as the fossilised remains of a previously unknown early human. These fragments consisted of parts of a skull and jawbone, said to have been collected in 1912 from a gravel pit at Piltdown, East Sussex, England...
was shown to be. Even if the "Precambrian rabbits" turned out to be genuine, they would not instantly refute the theory of evolution, because that theory is a large package of ideas, including: that life on Earth has evolved over billions of years; that this evolution is driven by certain mechanisms; and that these mechanisms have produced a specific "family tree" that defines the relationships among species and the order in which they appeared. Hence, "Precambrian rabbits" would prove that there were one or more serious errors somewhere in this package, and the next task would be to identify the error(s).
Benton pointed out that, in the short term, scientists often have to accept the existence of competing hypotheses, each of which explains large parts—but not all—of the observed relevant data.