Those of us who are passionate about all things natural, whether it's the food we put in or on our bodies, or the air we breathe, should probably carefully think about what what we mean by 'natural'. This is particularly important now that technological processes interact with almost every facet of nature.

The word 'natural' of course means lots of different things to different people. The term is much used by food, cosmetic and personal care companies, but how natural is natural? In this feature, our executive and scientific director, Rob Verkerk, grapples with the concept. He takes us on a multidisciplinary journey, through physics, chemistry and biology, and, ultimately, perhaps he raises more questions than he answers!

Feature Summary:

• A description of 'natural' is reliant on individual perception. Any examination of it comes with numerous limitations due to knowledge base, perception of reality, limitation of the English language, and, in our society, a general lack of public acceptance of ideas that don't hold a robust scientific base

• Base proposal: Natural means that which exists without intervention of the human species. But the concept is entirely anthropocentric, so it is seen only from the perspective, and with the attitudes and values, that are specific to the human species

• It is useful to evaluate the concept through the lens of major scientific disciplines. Dr Verkerk has done this using physics (e.g., gamma rays in relation to our interaction with outerspace vs human-engineered nuclear devices), chemistry (e.g., primordial elements that have existed in one form or another prior to the creation of planet Earth vs new-to-nature molecules) and biology (e.g., exchange of genetic material among species vs genetic manipulation by humans)

• It isn't possible to categorise things neatly as natural or unnatural. The extent and type of our intervention over things that pre-date the evolution of our species means that there is actually a continuum begween things that are 100% natural and those that are 100% synthesised by humans

• Our concern about whether something is natural or not may be down to our innate sense of responsibility for our activities in the world around us. Many of us are 'naturally' suspicious of things that are not natural. But this suspicion is perhaps little more than a reflection of our need to impart a sense of responsibility over that for which we are accountable.

What is 'natural'?

Multiple, parallel realities. Multiple universes. Multiple histories. Multiple opportunities. Over 10 dimensions. These are among the concepts we need to take on board if we are to accept some of the most current explanations for ‘what is’, as presently mapped by M-theory. M-theory, like string theory that preceded it, helps us to better understand reality. But these theories remind us of the limitation of human perception. And let’s remind ourselves that our reality is limited by our individual perception—and that our perception is, in turn, linked to the picture given to our conscious and subconscious mind from information gathered by our senses. These pictures are of course not only conditioned by the environment from which these data have been issued, they are also affected by our individual genetic and epigenetic landscape.

With this ‘super-scape’ in our mind’s eye, this essay seeks to explore the meaning of the word ‘natural’. There are numerous limitations to any examination of this subject, not least of all the limitation of our knowledge base and our perception of reality, the limitation of the English language (and the author’s use of it) and the lack of public acceptance—in contemporary western society—of ideas that do not hold a robust scientific base. While it might be just as appropriate to use a metaphysical or even spiritual or religious approach to investigate the subject matter, a more broadly scientific approach will be used, if for no other reason that this approach befits the multidisciplinary scientific background of the author.

Natural: an anthropocentric concept

In the barest of terms, I would like to propose that natural means that which exists without intervention of the human species. But categorisation between natural and unnatural will often be blurred, given that the extent and type of human intervention will need to be considered. As such, we must accept that the concept of ‘natural’ is in itself anthropocentric, meaning our perception of it is seen exclusively from the perspective of our own species, and typical human values and experience.

Humans represent just one of the multiple millions of species—both discovered and yet undiscovered—that exist, or have existed, on planet Earth. Strangely, while we regard the honey made by bees or the cyanide within apple seeds as natural, we might think differently about a toxic green slime made by an extra-terrestrial being. For the time being, let’s not only be anthropocentric, let’s also be focused primarily on those elements of our reality that most have come to accept as the human perception of reality, as experienced on planet Earth through our limited senses, awareness and intelligence. We will make this journey by considering the concept of ‘natural’ through lens of the three major disciplines of science: physics, chemistry and biology, as well as through the borders between them.

In some respects, the separation of these, and indeed of all other, scientific disciplines is a form of artificial reductionism used by humans to aid our understanding of complex processes. It is our limited intelligence that requires such reductionism, and it is reductionism that complicates our perceptions of the extent to which something is natural.

So, while studies of distinct types of atoms and specific combinations of particular atoms in the form of molecules constitutes the foundation of chemistry, the physics of sub-atomic particles can be equally important. For instance, the nature of an atom’s electron configuration, or the behaviour of sub-atomic particles in relation to each other and, in turn, their relationships with other factors, can be explained, even if only partially, both in terms of physics and chemistry. The way in which these atoms, and various configurations of bonded atoms as molecules, then interact with the biotic environment can be explained, not only in terms of physics and chemistry, but also in biological terms. And, as practitioners of the metaphysical would be likely to be among the first to ask, who is to say that these three scientific disciplines, at their current level of development, are sufficient to allow us to understand reality? That’s probably why the Theory of Everything, which aims to unify or explain through a single model the theories of all fundamental interactions of nature, is still such a topic of hot debate and is unlikely to emerge from the realms of theory any time soon.

With these limitations recognised and appreciated, how might we categorise substances or processes in relation to their naturalness? Should we, for example, regard a chemical molecule that exists naturally in the environment as unnatural if the very same chemical structure is assembled by human beings within a laboratory? Or should we give such chemicals a special classification, such as ‘nature-identical synthetic’? It probably makes sense to do so, as any form of sub-categorisation tells us additional information about the origins of a substance that would otherwise be lacking. And what if a naturally occurring microorganism is forced to metabolise nature-identical substances in a laboratory, producing metabolites or by-products not normally found in the natural environment? Shall we call these ‘bio-synthetics’? For the reason given above—it probably makes sense.

The same rationale can be applied to an F1 hybrid of dahlia that you may have cultivated in your garden. Or it could be applied to a variety of apple that doesn’t readily go brown after being bitten or cut? In the latter case, such apples, commonplace in today’s supermarkets, have been ‘selected’ by plant breeders because of their low content of the peroxidase, the enzyme which causes the familiar browning reaction following the exposure of the fruit tissue to oxygen. Retailers and consumers are said to prefer apples that don’t brown readily, but most don’t realise that the enzyme exists to protect the apple from attack by opportunistic pathogens. But if growers are ready with their arsenal of agro-chemicals, why should they be concerned with the peroxidase content?

Physics

In relation to our interaction with outer space, gamma rays exist naturally, being part of the cosmic radiation background to which we are exposed. We many not be able to explain every nuance and mechanism responsible for their generation, type or direction, but we think of background gamma radiation as a form of natural radiation precisely because it is not the result of our intervention.

By contrast, the high-energy gamma radiation experienced by the unfortunate inhabitants of Hiroshima and Nagasaki in 1945 cannot be seen as ‘natural’. Humans had worked hard to find ways of harnessing the radiant energy of specific types of atom. They did this within the confines of human-engineered nuclear devices. Since demonstrating the remarkable power that can be released from an atom of hydrogen, humans have continued to wield this power over their enemies as a deterrent. But this very same power, propagated through an expanding population of nuclear fission reactors, has also been harnessed to generate electricity.

We think of these two contrasting applications as unnatural because they occur as a result of our meddling with the laws of nature. The gamma radiation that kills, maims or generates electricity occurs naturally, but neither its application nor its level of exposure to human beings—to our knowledge—occurs in the natural world. Yet we feel comfortable describing the similar nuclear fission reactions as natural when they occur without any input from our species, whether this is within our own or adjacent galaxies, or perhaps, as some scientists believe, within the molten core of our planet.

Such a framework which characterises the quality and quantity of our exposure to specific elements within our environment serves a useful purpose when examining the human health consequences of particular technologies. The extremely low frequency electromagnetic radiation (ELF) that emanates from mobile telephones, telecommunications masts, DECT phones, wireless communication devices, powerlines and other sources of radiofrequency/microwave radiation (RF/MW) is a case in point. Humans have produced a plethora of sources of these forms of radiation and the resulting exposures dramatically exceed natural background levels. It is consequently the type and exposure level of ELF produced by human-made devices that concerns the scientists investigating the human health and environmental consequences of wireless communication technologies.

In further examining the concept of ‘natural’, let us now shift away from the field of physics and look instead at another scientific discipline; chemistry.

Chemistry

The ‘periodic table’ gives us a useful toolbox for understanding the world around us in chemical terms. The essential configuration of the table, albeit with many gaps compared with today’s version, was first proposed in 1869 by a Russian chemist by the name of Mendeleev.

Even today, chemists will admit there are more elements to be discovered, especially beyond our own planet, or as a result of nuclear experimentation. To-date, some 112 elements have been identified, and of these 94 are thought to be naturally-occurring, even though they might only exist in miniscule amounts or be short-lived. Around 80 elements are considered stable in their solid, liquid, or gaseous forms. Accordingly, they are regarded as ‘primordial elements’, in that they have existed in one form (isotope) or another prior to the creation of planet Earth. The last of these to be discovered was francium—in 1939. A small, more recently discovered group, typically itemised at the bottom of current versions of the periodic table, can be referred to as the ‘trace radioisotopes’ group. These are naturally-occurring products of radioactive decay. In relative terms, they are very short-lived and are found in the Earth’s crust or atmosphere in minute (trace) amounts. Plutonium-239 or uranium-236, produced following neutron capture within naturally-occurring uranium, are examples of such trace radioisotopes.

There is however one more category of elements in our current version of the periodic table. It is the ‘synthetic elements’. These are thought to be so unstable that, even if they were formed during the creation of our solar system, they have long since decayed. We consider these elements to be synthetic because they have only been found as products of experiments using nuclear reactors or particle accelerators. Elements like uranium, thorium, polonium and radon may be unstable, but since they are found naturally within the Earth’s crust or atmosphere, they cannot be regarded as synthetic. Rutherfordium, hassium and copernicium are examples of synthetic elements. Other elements have yet to be discovered or produced.

Following WWII, a massive explosion of organic chemistry occurred. This chemistry, characterised by the reaction of different elements, in different states, together with the single element carbon, provided much of the impetus for the chemical, agro-chemical and pharmaceutical industry. It allowed corporations to expand at an unprecedented rate, this capitalisation being based on the production of unique carbon-based chemical structures which could then be patented. Naturally-occurring molecules cannot be patented as their pre-existence in our natural environment precludes novelty which is required to successfully obtain a patent.

At the heart of the debate over what is a natural molecule, is of course, not just the origin of the elements that comprise the molecule, but the existence of the chemical in the absence of any manipulation by human beings. For some, understanding the divide between the naturally-occurring chemicals and those that are usefully described as ‘new-to-nature’ is a valuable way of understanding human responses to our chemical environment.

Biology

In evaluating what is constitutes a natural chemical, we should now move to the interface that divides chemistry and biology.

It is both incorrect and overly simplistic to argue that natural chemicals are safer to humans than artificially created ones. However, it has been amply demonstrated that human beings, along with all other animals, have developed complex detoxification systems for chemicals that occur naturally within our bodies or those ‘environmental chemicals’ to which we are exposed naturally. Many of these are ingested in our food, especially in plant-based foods. For most of us, our ingestion of food represents our most intimate exposure to the chemical world around us. Among the natural plant-based chemicals that are most protective against cancer, are actually those that are also toxic to insects, fungi or bacteria that seek to use those plants as a food source. The glucosinolates within brassica vegetables are good examples of this. But as Paracelsus argued around 450 years ago, it is “the dose that makes a poison”. So while such phytochemicals may indeed be toxic at high doses, their absence from our diet may be associated with an increased risk of disease.

Some of the most valuable herbal medicines have similar characteristics. Ancient herbal medicine traditions, such as Ayurveda from the Indian subcontinent and traditional Chinese medicine, were first documented over 4,000 years. But this documentation does not represent the first usage of plants for medical purposes. Plant medicine was likely well established in hominids many thousands, or hundreds of thousands, of years prior to this. This is supported by the fact that closely related primates such as chimpanzees, bonobos and orangutans are all accomplished users of plant medicines. It follows therefore that herbal medicine may have preceded the evolution of our species. Ingested in the right amounts, the products of particular plant parts, as well as their specific combination, can help support the proper functioning of metabolic processes within our bodies. In other words, such products can ‘heal’ us if we are diseased, or they can prevent the occurrence of disease. Most simply, they can promote homeostasis. Used incorrectly however, as with any toxic material, they can cause harm.

Importantly, if we are to accept the essential tenets of ‘natural selection’, as first proposed by Darwin, it may be that the duration of time to which we have been exposed to certain chemicals is of pivotal importance to the way by which we react to them. More exposure time means more adaptation time. Time is not only required to evolve ways of making particular chemicals less dangerous, time also offers the opportunity of enabling our bodies to utilise the beneficial properties of plants and other chemical constituents of our food.

Since life on our planet first emerged, probably a billion or more years ago, up until recently, an intricate dance between living things and non-living things has played out. In essence, this dance has existed between the biotic and abiotic natural world. The unnatural, human-created world only emerged in earnest following the Industrial Revolution of the 1800s. But the extent and nature of human interference in natural processes has catapulted forward dramatically in the last half century. In human evolutionary terms, 50 years is but the blink of an eye. It represents less than 9 seconds of a 24-hour clock depicting the possible 500,000 year evolution of our species.

Such a train of logic leads us of course to the subset of biology that we refer to as genetics. Life is coded by a series of chemicals arranged in highly specific ways. Our uniqueness can be explained genetically by understanding the precise arrangement of these chemicals to create a particular type of information. The information is in turn held within our DNA (deoxyribonucleic acid) within the sequence of pieces of DNA that we call genes. The Human Genome Project, as of 2003, informed us that all of the variation within our species is coded for by around 20,000 genes. These genes in turn express some 300,000 or so different polypeptides, enzymes and proteins, produced through the transcription of messenger RNA (mRNA). RNA differs from DNA only that it is comprised of a ribose sugar, rather than a deoxy ribose one. This revelation denigrated the ‘one gene-one polypeptide/enzyme/protein’ hypothesis that had been relied upon in molecular biology since it was first proposed by Beadle and Tatum in 1958, a proposal that led to the joint award of a Nobel Prize.

Genetic material can be exchanged among species, or, sometimes, other closely related organisms. In fact it is this fact that has been central to the taxonomic categorisation of our planet’s organisms. We therefore believe that there are preset, natural rules which govern the exchange of genetic material from the germline cells (gametes) of one organism to another. We think of this kind of genetic exchange as natural.

It is the disruption of these natural genetic rules that makes so many people question the wisdom of genetic engineering. Many are suspicious of the technology even without any awareness of scientific evidence of its harm to humans, other animals or other elements of the environment. Genetic manipulation—the domain of biotechnology—can therefore be seen to be responsible for products which can no longer be regarded as natural.

While a genetically-modified (GM) maize variety, viewed by governmental regulators as 'substantially equivalent' to its non-GM cousin, may look outwardly identical to its non-GM cousin, it should not be regarded as natural. It may have been modified through the incorporation of an alien genetic cassette to allow it to be resistant to one company’s herbicide, as is the case with Monsanto’s Roundup resistant crops. Alternatively, genetic material encoding for a toxic protein from a species of soil bacterium, Bacillus thuringiensis (Bt), may have been introduced to the maize plants’ DNA. Neither the method of gene insertion, nor the occurrence of the foreign genes expressing the specific trait, are able to occur without manipulation by humans. It is the breach of the natural laws governing genetic exchange that provides such grounds for concern among those apprehensive about the human health and environmental risks associated with outdoor release of genetically-modified organisms (GMOs).

While plant or animal breeding programmes also lead to genetic combinations that would not normally occur in nature, the processes that actually govern genetic exchange in such programmes still work within the parameters of the laws of nature.

Like with chemicals, the precise way by which humans manipulate genetic material raises further questions over how natural a given organism might be. Simple binary logic, in which something is natural or not, just make way for a continuum which tells us something about the extent of its naturalness.

Concluding remarks

Within the scientific disciplines of physics, chemistry and biology, we’ve been able to consider a rationale—from our unashamedly anthropocentric perspective—for what makes something natural.

We’ve been able to differentiate between the substance or entity, and the process. A chemical or radiation source might be natural, but is its existence, form, type or level of exposure within the ranges we might expect if humans had not intervened in any way? Alternatively, the process by which a substance, entity or organism is produced might be natural or unnatural. If the process is unnatural, we think of it as artificial even if the output from the process is identical to that which is yielded through processes that are independent of humans. Animal cloning or even in vitro fertilisation are thus regarded as unnatural processes, despite the fact that their progeny cannot be readily distinguished using current scientific means from those produced naturally.

We therefore must accept, as with so many forms of categorisation, that the simple distinction between natural and unnatural, or natural and synthetic or artificial, is necessarily crude. It may even be less than accurate. This greying of the boundaries between that which exists both with and without the intervention of our species yields a continuum. The continuum stretches, at one extreme, from that which occurs naturally in the absence of any interaction with the human species, to the other extreme, where things are generated through the activity of humans, the outputs being at odds with anything that might have existed previously. Most substances to which we are exposed, whether they are present in our food, our water or in the air we breathe, exist somewhere between these two extremes.

Whether a substance is identical to, a lot like, or only slightly like, one that exists naturally, might be of great consequence to our health, or even our survival. Equally, it might be of little or no significance. But whether it is of great, or little, significance, is not actually relevant to the positioning of the substance on the continuum.

We should keep reminding ourselves of the limits of our knowledge, perception and understanding. To an extra-terrestrial surveying our planet, the effects of activities of any of the organisms inhabiting the planet might be regarded as natural. Why should the effects wrought by one organism be segregated from those of millions of other organisms sharing the same planet?

As the organism responsible for such profound environmental change within our recent history, many are unsurprisingly concerned about what we are doing to our planet. These concerns are framed within our own awareness and particular systems of perception. They are also framed by our particular forms of intra-species (verbal and non-verbal) communication. Many of us will not yet be able to interpret the relevance of M-theory, or even understand how parallel universes or realities might exist. But most are guided by an innate and intuitive ‘feel’ which dictates that the more natural something is, the more acceptable it is.

Many also recognise that ‘natural’ doesn’t necessarily mean ‘safe’. In terms of today’s scientific understanding, especially within the discipline of toxicology, at least as important as the innate characteristics of the substance (or form of radiation) itself, is the nature and degree of our exposure to it. For toxicologists, dosage is seminal, although we might consider not blindly accepting over-simplistic notions about typical dose-response relationships. Toxicologists are however greatly limited by methodologies that consider the context of our exposures. Currently, very little attention is paid to the effects of mixtures of chemicals, both natural and unnatural, to which we are exposed daily. Scientific reductionism could be regarded as having hindered as well as helped our understanding of our natural environment, of which we are but one biotic component. On a daily basis we are learning more about the extraordinarily complex interactions that occur within our environment, using our much-loved, but somewhat limited, tools of physics, chemistry and biology.

We have, literally, only just begun scraping the surface of what is likely to really be going on. We should therefore be modest enough to avoid making claims as to the ultimate truth (if there is such a thing) concerning both our reality and the operation of the world around us. It is always helpful to keep thinking as 'big' as we can. After building understanding within our artificial scientific compartments, we then need to remove the compartments to achieve higher awareness. We then become multi-disciplinarians, thinking both horizontally as well as vertically. To push forward our awareness of our situation, we need to keep returning to the widest, most ‘macro’, unreduced and non-compartmentalised perspective we can find. M-theory provides us with one such perspective.

Our suspicion over processes, chemicals or forms of radiation that we view as unnatural is perhaps little more than a reflection of our need to impart a sense of responsibility over that for which we are accountable. By definition, we have no control over that which exists independently of ourselves. However, we can choose either to create or not create those things we view as synthetic, semi-synthetic, bio-synthetic or even nature-identical. In this way, we are therefore able to act as arbiters over those human-created elements of our perceived existence. We are technological beasts, as Prof Tim Taylor in his new book The Artificial Ape makes so clear. But that doesn't mean we need to degrade what is around us.

Long may such responsibility continue, on the grounds that it is coupled with the highest level of awareness and understanding that we can muster.

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