Vitalism
Vitalism, as defined by the Merriam-Webster dictionary, is
- a doctrine that the functions of a living organism are due to a vital principle distinct from physicochemical forces
- a doctrine that the processes of life are not explicable by the laws of physics and chemistry alone and that life is in some part self-determining
Where vitalism explicitly invokes a vital principle, that element is often referred to as the "vital spark," "energy" or "elan vital," which some equate with the "soul."
Vitalism has a long history in medical philosophies: most traditional healing practices posited that disease was the result of some imbalance in the vital energies which distinguish living from non-living matter. In the Western tradition, associated with Hippocrates, these vital forces were identified as the humours; Eastern traditions posited similar forces such as qi and prana. Vitalistic thinking has also been identified in the naive biological theories of children.

# Development
The notion that bodily functions are due to a vitalistic principle existing in all living creatures has roots going back at least to ancient Egypt.  While vitalist ideas have been commonplace in traditional medicine, attempts to construct workable scientific models date from the 1600s, when it was argued that matter existed in two radically different forms, observable by their behavior with regard to heat. These two forms of matter were termed organic and inorganic. Inorganic matter could be melted, but could also be restored to its former condition by removing the heat. Organic compounds "cooked" when heated, transforming into new forms that could not be restored to the original. It was argued that the essential difference between the two forms of matter was the "vital force", present only in organic material.
Aided by the invention of the microscope in the 16th century, the germ theory of disease challenged the role of vitalism in Western medicine, and the roles of the organs of the human anatomy in the maintenance of life became better understood, reducing the need to explain things in terms of mystical "vital forces". Nevertheless, vitalist ideas were still thought necessary by many scientists to explain how organisms maintained life.
In the early 19th century, Jons Jakob Berzelius, known as one of the "fathers" of modern chemistry, rejected mystical explanations of vitalism, but nevertheless argued that a regulative force must exist within living matter to maintain its functions. Carl Reichenbach later developed the theory of Odic force, a form of life-energy that permeated living things; this concept never gained much support despite Reichenbach's prestige. Vitalism is now often used as a pejorative epithet. By contrast, Ernst Mayr, co-founder of the modern evolutionary synthesis and a critic of both vitalism and reductionism, writing in 2002 after the mathematical development of theories underlying emergent behavior, stated:
It would be ahistorical to ridicule vitalists. When one reads the writings of one of the leading vitalists like Driesch one is forced to agree with him that many of the basic problems of biology simply cannot be solved by a philosophy as that of Descartes, in which the organism is simply considered a machine.....The logic of the critique of the vitalists was impeccable. But all their efforts to find a scientific answer to all the so-called vitalistic phenomena were failures.... rejecting the philosophy of reductionism is not an attack on analysis. No complex system can be understood except through careful analysis. However the interactions of the components must be considered as much as the properties of the isolated components.

# Mesmerism
A popular vitalist theory of the eighteenth century was "animal magnetism", in the theories of Franz Anton Mesmer (17341815). However, the use of the (conventional) English term animal magnetism to translate Mesmer's magnetisme animal is extremely misleading for three reasons:
- Mesmer chose his term to clearly distinguish his variant of magnetic force from those which were referred to, at that time, as mineral magnetism, cosmic magnetism and planetary magnetism.
- Mesmer felt that this particular force/power only resided in the bodies of humans and animals.
- Mesmer chose the word "animal", for its root meaning (from Latin animus = "breath") specifically to identify his force/power as a quality that belonged to all creatures with breath; viz., the animate beings: humans and animals.
So popular did Mesmer's ideas become that King Louis XVI of France appointed two commissions to investigate mesmerism; one was led by Joseph-Ignace Guillotin, the other, led by Benjamin Franklin, included Bailly and Lavoisier. The commissioners learned about Mesmeric theory, and saw its patients fall into fits and trances. In Franklins garden, a patient was led to each of five trees, one of which had been "mesmerized"; he hugged each in turn to receive the "vital fluid", but fainted at the foot of a 'wrong' one. At Lavoisiers house, four normal cups of water were held before a "sensitive" woman; the fourth produced convulsions, but she calmly swallowed the mesmerized contents of a fifth, believing it to be plain water. The commissioners concluded that "the fluid without imagination is powerless, whereas imagination without the fluid can produce the effects of the fluid." This was an important example of the power of reason and controlled experiment to falsify theories. It is sometimes claimed that vitalist ideas are unscientific because they are not testable; here at least is an example of a vitalist theory that was not merely testable but actually falsified.

# Foundations of chemistry
In the history of chemistry, vitalism played a pivotal role, giving rise to the basic distinction between organic and inorganic substances, following Aristotle's distinction between the mineral kingdom and the animal and vegetative kingdoms. The basic premise of these vitalist notions was that organic materials differed from inorganic materials in possessing a "vital force"; accordingly, vitalist theory predicted that organic materials could not be synthesized from inorganic components. However, as chemical techniques advanced, Friedrich Wohler synthesised urea from inorganic components in 1828. Wohler subsequently wrote to Berzelius, saying that he had witnessed "The great tragedy of science, the slaying of a beautiful hypothesis by an ugly fact." The "beautiful hypothesis" was vitalism; the ugly fact was a dish of urea crystals.
According to the conventional view of the subsequent progress of chemistry, further discoveries pushed aside the "vital force" explanation, as more and more life processes came to be described in chemical or physical terms. However, contemporary accounts do not support the claim that vitalism died when Wohler made urea. The Wohler Myth, as it was called by historian of science Peter J. Ramberg , originates from  a popular history of chemistry published in 1931 which, "Ignoring all pretense of historical accuracy, turned Wohler into a crusader who made attempt after attempt to synthesize a natural product that would refute vitalism and lift the veil of ignorance, until 'one afternoon the miracle happened'."
Some of the greatest scientific minds of the time continued to investigate these vital properties. Louis Pasteur, shortly after his famous rebuttal of spontaneous generation, made several experiments that he felt supported the vital concepts of life. According to Bechtel, Pasteur "fitted fermentation into a more general programme describing special reactions that only occur in living organisms. These are irreducibly vital phenomena." In 1858, Pasteur showed that fermentation only occurs when living cells are present and, that fermentation only occurs in the absence of oxygen; he was thus led to describe fermentation as life without air. He found no support for the claims of Berzelius, Liebig, Traube and others that fermentation resulted from chemical agents or catalysts within cells, and so he concluded that fermentation was a "vital action".

# Psychology
Perhaps more than any other area of science, psychology has been rich in vitalist concepts, particularly through the ideas of Sigmund Freud and Carl Jung. Freud was a student of the notable anti-vitalist Hermann von Helmholtz, and initially struggled to express his concepts in strictly neurological terms. Abandoning this effort as fruitless, he became famous for his theory that behaviour is determined by an unconscious mind, of which the waking mind is unaware. In 1923, in The Ego and the Id, he developed the concept of "psychic energy" as the energy by which the work of the personality is performed.
Although Freud and Jung remain hugely influential, psychology has made a determined effort to rid itself of the most mystical of these concepts in an attempt to appear more like the "hard" sciences of chemistry and physics.  Although research within cognitive neuroscience has made substantial progress in explaining mental processes such as perception, memory and motivational states such as anger and fear, larger concepts such as mind and intelligence, remain essentially higher level constructs, with observable neural correlates distributed throughout the  
The neuroscientist Roger Sperry, in his Nobel Prize lecture in 1981, described modern scientific concepts of the nature of consciousness and its relation to brain processing as follows:
The events of inner experience, as emergent properties of brain processes, become themselves explanatory causal constructs in their own right, interacting at their own level with their own laws and dynamics.  The whole world of inner experience (the world of the humanities) long rejected by 20th century scientific materialism, thus becomes recognized and included within the domain of science."
Anti-reductionism has been identified as a problem in psychology. Thomas (2001) states that "It is now generally considered that biology had to rid itself of vitalism to enable significant progress to occur.  It is suggested that psychology will develop as a science only after it rids itself of  anti-reductionistic, 'emergentism'."

# Developmental biology
Caspar Friedrich Wolff (1733-1794) is considered to be the father of epigenetic descriptive embryology. In his Theoria Generationis (1759), he endeavoured to explain the emergence of the organism by the actions of a "vis essentialis", an organizing, formative force, and declared that "All believers in epigenesis are Vitalists." However, even early vitalists were aware that the vital forces that they proposed were to be understood metaphorically, not literally. For example, Johann Friedrich Blumenbach, established epigenesis as the model of thought in the life sciences in 1781, with his publication of Uber den Bildungstrieb and das Zeugungsgeschafte. Blumenbach cut up freshwater polyps and established that the removed parts would regenerate; he inferred the presence of a "formative drive", an organic force, which he called  "Bildungstrieb". He pointed out that this, "like names applied to every other kind of vital power, of itself, explains nothing: it serves merely to designate a peculiar power formed by the combination of the mechanical principle with that which is susceptible of modification."
Vitalism was also important in the thinking of later teleologists such as Hans Driesch (1867-1941).
In 1894, Driesch wrote a theoretical essay entitled Analytische Theorie der organischen Entwicklung, in which he declared that
This comment came from his experiments on sea urchin eggs. Driesch, already a famous biologist, became a vitalist, but his reputation as a biologist deteriorated in later life. He moved to Heidelberg and became a Professor of Natural Philosophy, seeing his vitalism an extension of Immanuel Kant's notion that the organism develops as if it had a purposeful intelligence.

# Foundations of medicine
While conventional medicine has distanced itself from the less reductionistic and more vitalistic approach of traditional medicine, some complementary medical fields continue to espouse various guises of vitalistic concepts and worldview.  The National Center for Complementary and Alternative Medicine (NCCAM) classifies CAM therapies into five categories or domains:
- alternative medical systems, or complete systems of therapy and practice;
- mind-body interventions, or techniques designed to facilitate the mind's effect on bodily functions and symptoms;
- biologically based systems, including herbalism;
- manipulative and body-based methods, such as chiropractic and massage therapy; and
- energy therapy.
The therapies that continue to be most intimately associated with vitalism are bioenergetic medicines, in the category of energy therapies.  This field may be further divided into bioelectromagnetic medicines (BEM) and biofield therapies (BT).  Compared with bioenergetic medicines, biofield therapies have a stronger identity with vitalism.  Examples of biofield therapies include therapeutic touch, Reiki, external qi, chakra healing and SHEN therapy.  Biofield therapies are medical treatments in which the "subtle energy" field of a patient is manipulated by a biofield practitioner.  The subtle energy is held to exist beyond the electromagnetic (EM) energy that is produced by the heart and brain.  Beverly Rubik describes the biofield as a "complex, dynamic, extremely weak EM field within and around the human body..."
Acupuncture and chiropractic emphasize a holistic approach to the cause and treatment of disease (see main articles on these subjects). For example, in a paper named "The Meanings of Innate",  Keating says that "Innate Intelligence" in chiropractic can be used to represent four concepts:  a synonym for homeostasis, a label for a doctor's ignorance, a vitalistic explanation of health and disease, and a metaphysical premise for treatment.
The founder of homeopathy, Hahnemann, promoted an immaterial, vitalistic view of disease: "...they are solely spirit-like (dynamic) derangements of the spirit-like power (the vital principle) that animates the human body." As practised by some homeopaths today, homeopathy simply rests on the premise of treating sick persons with extremely diluted agents that - in undiluted doses - are deemed to produce similar symptoms in a healthy individual. Nevertheless it remains equally true that the view of disease as a dynamic disturbance of the immaterial and dynamic vital force is taught in many homeopathic colleges and constitutes a fundamental principle for many contemporary practising homeopaths.

# "New Age" mysticism
Vitalism is also an aspect of many "New Age" theories. Examples include Rupert Sheldrake's concept of "morphic resonance" - the idea of telepathy-type interconnections between organisms and of collective memories within species, and revivals of Reichenbach's Odic force, which is sometimes used to explain colored auras.  Anthroposophy, founded by Rudolf Steiner, is a quasi-religious cult whose teachings, in Steiner's words, lead "from the spirit in the human being to the spirit in the universe." An early form of sustainable agriculture, biodynamic agriculture, was fostered by this movement.

# Relation to emergentism
In terms of the biology of the cell, a variation of vitalism can be recognized in contemporary molecular biology; for example in the proposal that some key organising and structuring features of organisms, perhaps including even life itself, are examples of emergent processes in which complexity arises out of the interactions of the chemical processes which occur in the cell; When individual chemical processes form interconnected feedback cycles which produce products perpetuating these cycles rather than unconnected products, they can form systems with properties that the reactions, taken individually, lack.
Whether emergent system properties should be characterized with traditional vitalist concepts is a matter of semantic controversy. In a light-hearted millennial vein, Kirshner and Michison call research into integrated cell and organismal physiology molecular vitalism.
According to Emmeche et. al. (1997):
"On the one hand, many scientists and philosophers regard emergence as having only a pseudo-scientific status. On the other hand, new developments in physics, biology, psychology, and crossdisciplinary fields such as cognitive science, artificial life, and the study of non-linear dynamical systems have focused strongly on the high level 'collective behaviour' of complex systems which is often said to be truly emergent, and the term is increasingly used to characterize such systems."
Emmeche et. al. (1998) state that "there is a very important difference between the vitalists and the emergentists: the vitalist's creative forces were relevant only in organic substances, not in inorganic matter. Emergence hence is creation of new properties regardless of the substance involved." "The assumption of an extra-physical vitalis (vital force, entelechy, elan vital, etc.), as formulated in most forms (old or new) of vitalism, is usually without any genuine explanatory power. It has served altogether too often as an intellectual tranquilizer or verbal sedativestifling scientific inquiry rather than encouraging it to proceed in new directions."

# Critical opinions
Opponents of vitalism believe that it is pseudoscience, since its core ideas are metaphysical and impossible to prove or disprove using scientific method.
Bechtel and Richardson state that vitalism lacks credibility because it is often viewed as unfalsifiable, and is "therefore a pernicious metaphysical doctrine."  While many vitalistic theories have in fact been falsified, notably Mesmerism and the phlogiston theory (see above), the pseudoscientific retention of these falsified theories continues to this day in a fashion that ignores the testability criterion of the scientific method.
For many scientists, "vitalist" theories are unsatisfactory "holding positions" on the pathway to mechanistic understanding. In 1967, Francis Crick, the co-discoverer of the structure of DNA, stated And so to those of you who may be vitalists I would make this prophecy: what everyone believed yesterday, and you believe today, only cranks will believe tomorrow.
Alan Sokal published an analysis of efforts within the field of nursing to describe vitalistic beliefs as "new science" (Pseudoscience and Postmodernism: Antagonists or Fellow-Travelers?). Pseudoscientific accounts within the field of nursing of practices such as therapeutic touch were reviewed by Sokal and he concluded, nearly all the pseudoscientific systems to be examined in this essay are based philosophically on vitalism. Sokal also noted that, "Mainstream science has rejected vitalism since at least the 1930s, for a plethora of good reasons that have only become stronger with time.
In his book "Kinds of Minds", philosopher Daniel Dennett wrote, "Dualism...and Vitalism (the view that living things contain some special physical but equally mysterious stuff -elan vital- have been relegated to the trash heap of history...." (Chapter 2).
Joseph C. Keating, Jr., PhD, discusses vitalism's past and present roles in chiropractic and calls vitalism "a form of bio-theology." He further explains that:
Vitalism is that rejected tradition in biology which proposes that life is sustained and explained by an unmeasurable, intelligent force or energy. The supposed effects of vitalism are the manifestations of life itself, which in turn are the basis for inferring the concept in the first place. This circular reasoning offers pseudo-explanation, and may deceive us into believing we have explained some aspect of biology when in fact we have only labeled our ignorance. 'Explaining an unknown (life) with an unknowable (Innate),' suggests philosopher Joseph Donahue, D.C., 'is absurd'.
He views vitalism as incompatible with scientific thinking:
Chiropractors are not unique in recognizing a tendency and capacity for self-repair and auto-regulation of human physiology. But we surely stick out like a sore thumb among professions which claim to be scientifically based by our unrelenting commitment to vitalism. So long as we propound the 'One cause, one cure' rhetoric of Innate, we should expect to be met by ridicule from the wider health science community. Chiropractors cant have it both ways. Our theories cannot be both dogmatically held vitalistic constructs and be scientific at the same time. The purposiveness, consciousness and rigidity of the Palmers Innate should be rejected.
He also mentions Skinner's viewpoint:
Vitalism has many faces and has sprung up in many areas of scientific inquiry. Psychologist B.F. Skinner, for example, pointed out the irrationality of attributing behavior to mental states and traits. Such 'mental way stations,' he argued, amount to excess theoretical baggage which fails to advance cause-and-effect explanations by substituting an unfathomable psychology of 'mind'.
According to Williams, "today, vitalism is one of the ideas that form the basis for many pseudoscientific health systems that claim that illnesses are caused by a disturbance or imbalance of the body's vital force." "Vitalists claim to be scientific, but in fact they reject the scientific method with its basic postulates of cause and effect and of provability. They often regard subjective experience to be more valid than objective material reality."
Stenger states that "This term is applied in biochemistry to refer to the readily measurable exchanges of energy within organisms, and between organisms and the environment, which occur by normal physical and chemical processes. This is not, however, what the new vitalists have in mind. They imagine the bioenergetic field as a holistic living force that goes beyond reductionist physics and chemistry."
Vitalism, or bioenergy, is often explained as being an electromagnetic(EM) field and advocates argue that this idea is supported by the theory of quantum physics.  Joanne Stefanatos states that "The principles of energy medicine originate in quantum physics."  Victor Stenger offers several explanations as to why this line of reasoning may be misplaced.  He explains that energy is recognized as matter and exists in discrete packets called quanta.  The quanta of EM fields are known to be photons.  Energy fields are composed of their component parts and so only exist when quanta are present.  Therefore energy fields are not holistic, but are rather a system of discrete parts that must obey by the laws of physics.  This also means that energy fields are not instantaneous.  These facts of quantum physics place limitations on the infinite, continuous field that is used by some theorists to describe so-called "human energy fields".  Stenger continues, explaining that the effects of EM forces have been measured by physicists as accurately as one part in a billion and there is yet to be any evidence that living organisms emit a unique field.