"If we consider the animal kingdom, and notice that among the quadrupeds there is none whose physical parts and functions, particularly the internal ones, are not quite similar, may we not readily believe that there was never more than one primeval animal, the prototype of all, while nature only lengthened, shortened, transformed, multiplied or obliterated some of its organs?" - Denis Diderot, Thoughts on the Interpretation of Nature (1754)
Though Darwinists and neo-Darwinists have seldom acknowledged it, there were plenty of evolutionists before Darwin, including such celebrities as Diderot, Kant and Goethe. The views of most 18th century evolutionists can be most easily summarised with reference to the most prominent of their number, Jean-Baptiste Lamarck. In the simplest terms, what Lamarck believed was that every living organism was the product of the accumulated responses that all its ancestors had made to the environments they had inhabited. In particular, he paid a lot of attention to the issue of Use and Disuse of organs in animals. In order that environmental and behavioural effects could be cumulative, the central tenet of Lamarckism was the inheritance of acquired characteristics, which means that offspring can build on the achievements of their ancestors. The changes that occur to an organism during its lifetime, as a result of behaviour, diet, climate or illness, could (though not necessarily would) be transmitted to any subsequent offspring. All pre-Darwinian evolutionists took it as read that acquired characteristics were inheritable in some degree.
The relatively new idea that Darwin and Wallace became famous for introducing into evolution theory was the issue of Natural Selection, whereby every living organism owes its existence to the fact that all its ancestors were lucky enough to have inheritable characteristics which suited them to the environments they inhabited. Those fortuitous characteristics prevented all those ancestors from being culled by cruel nature before they managed to reproduce and pass on those characteristics to some of their offspring. But Natural Selection is, in itself, only the guiding system of evolution; it says that, given there evidently is variation between and within species, the organisms which leave descendants tend to be the ones whose inheritable variations favour their survival over their competitors. The hidden assumption behind Natural Selection, especially amongst neo-Darwinists, is that the source of variation is random. Though Darwin did make occasional references to the concept of spontaneous variation, he had very little to say about the cause of variation, which is where one must look for the source of evolutionary change. Consequently, it is a supreme irony that one of the most famous books of all time, "The Origin of Species", is notable for the fact that it has almost nothing to say about the origin of species.
In the mid-19th century, there was no natural conflict between Darwinism and Lamarckism, since one concentrated on the guiding system of evolution and the other concerned itself with the source of inheritable variations. Consequently, it was possible to regard Darwinism as a complimentary development of Lamarckism, which is exactly what the famous German evolutionist, Ernst Haeckel, did. (See Haeckel essay) As it happened, throughout his later life as a renowned evolutionist, Darwin also increasingly accepted that one of the sources of variation was the inheritance of acquired characteristics. In modern-day terms, Darwin was a Lamarckist. What this shows is that, in order to be a believer in Lamarckian inheritance, you do not need to believe it is the only factor in evolution; nor do you need to deny the importance of Natural Selection, either in its literal or Darwinian sense. However, neo-Darwinists have always been keen to create a conflict between Darwinism and Lamarckism by presenting them as exclusive alternatives.
Following Darwin's death in 1882, a German professor of zoology, August Weismann, claimed that the germ-plasm took a continuous line of descent from grandparents to grandchildren without being affected by the parents in between. In other words, the contents of sperm and eggs are unaffected by their possessors. As a consequence of this, Weismann claimed that the inheritance of acquired characteristics was impossible. Lots of Darwinists believed him (including Wallace), and Darwinism became censored in respect of Lamarckian inheritance. This resulted in a major row in evolutionary circles in which everyone was forced to consider themselves to be either Weismannists or Lamarckists.
In the early 20th century, following the rediscovery of Mendel's famous 1865 paper on heredity and lots of research into the contents of cell nuclei (the chromosomes), it gradually became apparent that the material of biological inheritance (in the form of the DNA from which chromosomes are 'essentially' made) could not be affected by environmental influences in any responsive way. Effectively, Weismann and Mendel were both proved right within the context of the simple materialist paradigm that has pervaded almost all science. Therefore, the inheritance of acquired characteristics became official heresy in biological circles (except briefly in the USSR) and Lamarckism became banished to the realms of vitalist philosophy. The marriage between censored Darwinism and Mendelism became known as neo-Darwinism. During that period, a Danish botanist called Wilhelm Friedrich Johannsen had coined the term 'gene' as the material unit of biological inheritance (with chromosomes being made of a small proportion of genes and a very large proportion of 'junk' DNA), which caused the word 'genetic' to mean both 'inherited' and 'contained in genes'. That suited the neo-Darwinian scientific establishment, which came to regard DNA as the sole and universal Inheritance System. Consequently, the perennial Nature v. Nurture debate became translated as Genes v. Environment. In Lamarckian terms, nature is inherited nurture, being the accumulated effects of past environments; so the real issue is not what genes an organism is born with but how its ancestors used them.
Throughout the entire evolution debate of the past two centuries, there has never been a shred of philosophically-rigorous evidence against the inheritance of acquired characteristics, and the empirical evidence has always been in favour of it. There are mountains of circumstantial evidence from nature which can be explained much more easily by Lamarckism than by neo-Darwinism. There have been numerous experiments done which have demonstrated the apparent inheritance of acquired characteristics, including those by Edouard Brown-Sequard and Karl Semper in the 19th century, and those of Paul Kammerer and Conrad Waddington in the 20th century. Recently, the phenomenon of second-generation Thalidomide symptoms can only be explained by reference to non-genetic inheritance, and some behind-the-scenes scientists have been reporting new evidence of Lamarckian inheritance, including the long-term consequences of the Dutch Hunger Winter of 1944-5. Yet neo-Darwinists have always denied all that evidence, describing Lamarckism as discredited and its adherents as ridiculous, simply because they cannot reconcile it with their belief that genes must be the sole determinants of inheritable characteristics. The reality is that genes are only known to be the coded determinants of an organism's chemical - and hence medical - abilities; no satisfactory mechanism has ever been offered as to how the ability to do certain chemical processes could also determine morphological and behavioural characteristics. That is pure supposition.
In recent years, the issue of gene expression has come very much to the fore, and it is in this field that the most doubts have been expressed, even by some scientists, about the orthodox neo-Darwinian view. Although we are learning a lot about all the material intermediaries involved in gene expression, ultimately there is no single trigger to the chain of events that lead to any particular gene being expressed. There are lots of inter-dependent factors involved. So now, at long last, scientists are beginning to realise and acknowledge that genes may not be the sole determinants that neo-Darwinism has always supposed them to be. Whatever other factors determine inheritable characteristics, they are undoubtedly not constrained by the limitations of Mendelism.
When a gene becomes expressed, the section of double-stranded DNA containing that gene opens up into a loop, like the effect of pulling the two strands of a piece of rope apart from the middle. One of the two exposed strands becomes 'read' and, by a very complicated procedure which is well understood in terms of how it happens but scientifically incomprehensible in terms of why it happens the way it does, a particular type of protein molecule becomes manufactured. The reason why a gene needs to become expressed within any cell is either because the cell needs an enzyme due to an excess of the type of molecule that the enzyme degrades, or because the cell needs an enzyme (or other protein) due to a deficiency that the enzyme will help to fill. In neither case does it seem at all plausible that an automatic cause and effect chain, between the excess or deficiency and the expression of the gene, can be operative. That would be like saying that snowfall is the direct cause of snow ploughs and sledges coming out. Why does the need for a particular enzyme result in the particular gene that creates that enzyme being expressed? It would appear that something within the cell is making 'rational' decisions, based on past experience and habit. Inevitably, that 'something' must equate with LIFE, which biology has singularly failed in its brief to explain.
Epigenetics was coined by Conrad Waddington as 'the branch of biology which studies the causal interactions between genes and their products which bring the phenotype into being'. For the purposes of this article, it concerns those chemical processes and changes that go on in a cell that are not instigated by the cell's own genes. Amongst other things, epigeneticists have established that chromosomes are not as invulnerable to change as they were previously thought to be. It has been known since the end of the 19th century that chromosomes are not just composed of DNA; the DNA strands are wrapped around protein molecules, which had always been assumed to be inert structural components. It has now been discovered that these proteins can spread out or bunch up to make genes more or less accessible in different types of cells. Also, and more importantly, there are various ways in which chromosomes can acquire marks which promote or inhibit the expression of those genes. These marks, which are usually molecules that become attached to the DNA strands or proteins in particular places within the chromosomes (including the 'junk' DNA), originate within body cells in response to experience. In other words, the cells themselves are keeping a record of where the useful genes are and under what circumstances they are to be used. Thus, acquired characteristics have been described in molecular terms.
Different cell types (e.g. skin, liver, brain etc) have different epigenetic markings, which are what cause them to be the type they are. Furthermore, when marked chromosomes are replicated, the replicas contain the same markings as the original, so a replicated liver cell becomes another liver cell. This is believed to occur through a template effect, whereby the cell uses the original as a template for the replica. There is a lot of evidence, acquired by behind-the-scenes epigeneticists in recent years, that during cell division, and other forms of asexual reproduction, even the acquired chemical attributes of a cell are transmitted to its progeny. In other words, during asexual reproduction, Lamarckian inheritance definitely does occur, by a process that is scientifically understood. There is also considerable evidence that this occurs in sexually-reproducing species too, though this is not so well understood. The reason for this is that fertilised eggs are virtually wiped clean of epigenetic markings on the genes, which has to be the case so the subsequent cells can develop into any cell type (though the genes needed for replication of chromosomes need to be switched 'on'). If every fertilised egg starts with an epigenetic clean slate, then it would appear that genes must be the sole determinants of inheritable characteristics.
However, it is not the case that fertilised eggs start with epigenetic clean slates. One of the important discoveries epigeneticists have made is that 'junk' DNA, which was previously thought to be redundant, plays an important role in gene expression. Furthermore, the Epigenetic Markings On the 'Junk' Inheritance System (EMOJIS) do not get wiped off in the fertilised egg. EMOJIS are needed in order to trigger the epigenetic markings on the genes which cause cell differentiation. This implies that EMOJIS are the ultimate controller of epigenetics and the recorder of epigenetic changes. In other words, EMOJIS form an inheritable Epigenetic System which controls the epigenetic markings on genes in different cell types. That controls gene expression, so the Epigenetic System is responsible for genetic organisation. Any changes to the epigenetics in different cell types as a consequence of experience can accumulate as altered EMOJIS and get passed on to any replicas. The only problem is that the production of replicas by cell division is a localised business. Skin cells produce skin cells and only sperm-line cells produce sperm.
Epigeneticists can offer no mechanisms whereby the changes to EMOJIS in body cells get transmitted, via the fertilised egg, to the next generation. And that is what is needed in order to explain Lamarckian inheritance in sexually-reproducing species. Since 1981 Rupert Sheldrake's hypothesis, which I support in its essential premise, has been that the answer lies in some as-yet-undetectable communication system which he called morphic fields. If epigeneticists suggested that their template effect might be 'at a distance' rather than just in situ, that would have been enough, but they probably feel that such a suggestion would be moving into Sheldrake territory, and hence be scientifically unacceptable. However, as I see it, they have got to move into Sheldrake territory. The replication machinery in a cell does not have eyes or hands. In what way does the actual presence of a marked chromosome assist in its exact replication by blind machinery? There is no 'equal and opposite' physical template like there is in DNA replication. The replication of chromosomes, complete with markers, is no more understandable if it happens within a cell than if it happens in adjacent cells, or even adjacent organisms (such as an embryo and its mother). What I am suggesting is that the shapes and add-on extras that proteins and chromosomes adopt during their formation is determined by something akin to morphic fields which are transmitted by the same proteins or chromosomes, which need not be in the same cell but probably need to be not far away. (My main difference with Sheldrake is over the range of morphic influence in biological systems.) Thus, marked chromosomes can be transmitted to progeny, even in sexually-reproducing species, which the empirical evidence shows they are.
One of the things that epigeneticists have discovered is that, in mammals at least, there is often a difference in the way that embryos treat chromosomes from the male parent or the female parent. Under the above hypothesis, that difference is reflected in the way that epigenetic change is transmitted by the two parents. In males, the sperm are created just before the time of conception, so the sperm can contain any epigenetic changes that have been made by the male during its lifetime to its EMOJIS. That only requires that the epigenetic change is sufficiently pronounced to affect chromosome replications all the way from the affected body cells to the sperm-line cells. In females, the ova are created very early on, long before the future mother has had any experience of life. In that case, the embryo receives its epigenetic changes by replicating its mother's chromosomes, complete with any altered EMOJIS, while it is developing in the womb. So we get our epigenetic changes from our two parents by different routes.
Epigeneticists have been known to compare genetic markers to volume controls on the genes, which get adjusted, either up or down, through the generations. That means that genes effectively have messages written on them like, "Do not, under any circumstances, try me", "In case of emergency, try me", "When you're stuck, try me", "Be like eight out of ten previous owners, and try me", "You won't be sorry if you try me" or "I'm the new kid on the block, so try me". Since neo-Darwinists have always maintained that the course of evolution has been determined by the mere existence of genes, which all just said "Try me", the effect on evolution of inherited regulatory controls upon gene expression could have been enormous. In effect, what we are seeing is Lamarck's favoured evolutionary mechanism of Use and Disuse, but of genes rather than organs, but organs are only created by the expression of genes anyway.
Most epigenticists are prepared to state that the inheritance of acquired characteristics does happen, but they still cautiously suggest that it may not be particularly significant for evolution, which is basically neo-Darwinian. That need not be the case. Lamarckian Inheritance From Epigenetics (LIFE) could be doing much more than that. The course of evolution could have been determined by the passage of Epigenetic Systems (or the Genetic Organisation System's History - GOSH!), which use genes as tools, in the same way a carpenter/mechanic/plumber uses tools. The tools may be essential for the job, but it is still a c/m/p doing the job on the basis of previous experience. The introduction of a new gene, or the loss of a former gene, could still disturb the Epigenetic System in a Mendelian manner, and organisms would still be subject to Natural Selection, but the System itself would owe everything to its historical development and experiences and almost nothing to the actual genetic make-up of the organism it is operating in. In other words, the main player in "The Course of Evolution" could have been Lamarckism, whilst Natural Selection and Mendelism have merely played supporting roles.
As an illustration of what I mean, it has been well publicised that chimpanzees are genetically almost identical to us. Indeed, almost all mammals are genetically very similar. They all have approximately 20,000 genes, and they all have eyes, brains, livers, bones, hearts, muscles, skin and hair etc. The differences between all mammals are due to the fact that those organs have different sizes, shapes and distributions. That could have been caused by the divergences of the Epigenetic Systems and the accumulated changes made to the EMOJIS in the separated systems. They in turn could have been caused by environmental effects.
In effect, what has happened is that Lamarckism has had its name changed to Epigenetics. Laboratory epigeneticists seldom refer to Lamarckian inheritance or Lamarckism by name, even though that is what their evidence is uncovering. The reason for this is probably that they want their evidence to be taken seriously, and they also want to continue to get funding for their research. If they refer to Lamarckism by name, they fear that they will be held up to ridicule and their funding will be cut. For its part, the scientific Establishment does not want to admit that, for two centuries, they have been wrong to castigate Lamarck, initially for proposing evolution theory at all, and subsequently for the particular theory he proposed. The most adamant present-day scourgers of Lamarckism are hoping to hold off that admission until after they have retired or even died, in line with Max Planck's quote below. That, of course, is my opinion, which is shared by some thinkers and scientists, in Britain at least. However, that admission has got to come sooner or later, and I am hoping that this article will help to bring it about. My personal motivation is to rescue the tarnished reputations of several people, and most notably that of Lamarck, so the issue of the truth coming out is very important to me.
"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it." - Max Planck, 1948, amusingly paraphrased as "Science advances one funeral at a time."