Scientific terms do need protection

'Science is supposed to use words with care and preferably strict definitions'

I would certainly join a Society for the Protection of Scientific Terms. The urge was particularly strong after I had experienced Shiatsu, which is like acupuncture without needles, not unpleasant. But I was then told that I had very low kidney energy. The idea that pounding and pressing bits of my body could detect such a localised quantity was irrational, absurd, and finally infuriating.

Science is supposed to use words with care and preferably with strict definitions. Non-scientists have, not for the first time – just think of chaos, relativity, and the uncertainty principle – taken a scientific term and used it in a way that seems to be totally inappropriate; but because the word is from science it gives it a spurious validity. Nowhere is this more evident than with the widespread use of the term energy in what is politely called alternative or complementary medicine, but bears no, or little relation to science-based medicine. I recognise that the word may have been used long before the scientific basis of energy was established, but that was some 200 years ago.

Greek philosophers thought of energy as a fluid permeating a substance. Energy medicine apparently accepts the existence of a subtle energy system within the body, holding that manipulating the body energetically can cause physical, material changes to take place. Matter and energy are understood to be completely interchangeable – in fact, they are regarded as being, ultimately, the same thing. (Linking this with Einstein's ideas is totally spurious). The body is viewed as an integrated whole. Thus Ayurvedic medicine claims that there are canals in the body carrying energy and qi energy channels are central to acupuncture, crystal healing is based on transmission of energy, and faith healing also works by channelling energy. There is no indication of how this energy is generated or what its nature is.

One of the earliest uses of energy, psychic energy, was that of Freud which provided a hydraulic model of the mind. He suggested that the operation of the brain was governed by the energy of the nerve cells which tried to keep the energy to a minimum. Repression for example, requires constant expenditure of energy by the Ego. He proposed that all laughter-producing events are pleasurable because they save psychic energy.

All this bears no believable relation to the fundamental concept of energy used in science. Energy is the capacity for doing work as recognised by my hero Galileo. Lifting a weight by a pulley requires a force moving through a distance and the product of the force and the distance is work and is equivalent to energy. The unit for energy is the joule which is defined as force of one newton acting over one meter. All energy is associated with motion – the lifted weight has potential energy for moving down when it is converted into kinetic energy. There is also chemical energy in the movement of molecules and thermal energy from heat. Energy is never lost, merely converted into another form. The main source of energy in our world is radiation from the Sun produced by thermo-nuclear reactions.

Cells use energy to maintain their complex organisation and to grow and multiply and move. This energy comes from chemical reactions. The currency for most energy requiring processes in cells – the cell's "euro" – is adenosine triphosphate (ATP), which can provide energy when one of the three phosphates is removed. The food we eat together with oxygen generates the ATP currency. It is ATP that provides the energy for the function of our liver, kidneys, and brain .There is no evidence for a chemical or biological entity such as qi or kidney energy. Such misuse of a scientific term does matter for it gives a false credibility to the explanations offered as to how treatments such as acupuncture might work. I am not suggesting here that the techniques of alternative medicine do not help patients or that their effect is entirely due to the placebo effect but it is totally misleading to claim that energy underlies their effect. The continued misuse of the term should make one very suspicious of those who persist in misusing it.

The writer is professor of biology as applied to medicine at University College London