It is said that chi flows through the body organs such as lungs etc. Then the chi can physically affect the body organs. But the body moves from place to place. So chi must follow the body from place to place. This suggest that we should consider body-chi interaction akin to the electromagnetic interaction. Well we could 'answer' these questions the usual way the careless 'gurus' do: 'it is beyond understanding'. But why should we do that without making any attempt to understand? Furthermore it is parts of objects that move together wherever the object goes that make us say 'the parts are bonded together'. There is no more understanding even in the so called 'physical world'. The key to presenting a good scientific theory of chi, then, is to reconsider fundamental interaction of particles. Specifically, chi must be a weakly interacting field, interacting with charged particles via a decouple-able 'fifth force'. Or at least so must it appear to a scientist.
Weak interaction is the interaction with our version of charges, but 'strong interaction' will be an interaction with a de-couple-able fifth force version of charge. Compare this idea to that of 'Weakly Interacting Massive Particles' (WIMPS), candidate for the so called 'dark mattr'. All it takes for particle to seam ' intangible' is for it to cease interacting with electromagnetic force! If it doesn't interact with photons then it can't be seen. So we no longer use the old version 'it is immaterial' to answer the question why chi cannot be seen. Use the modern version; chi does not interact with the electromagnetic(i.e. photonic field). We now understand that it is not belonging to a class dubbed 'material' that makes things visible . In fact it is not matter at all hence 'dark matter' to mean some 'intangible ' entity. It is strictly electromagnetism. Without the latter, matter would be effectively undetectable as it is 99.9999999 percent empty. Thus light would easily pass through it and our fingures, tongues etc would to the same, hence complete intangibility. So we cannot continue using the naive 17nth century 'immaterial' which negates matter rather than forces in the definition of unseen. What more? If spirit interacts with photons, it will look completely like what we (perhaps un-inspiredly) dubb 'matter'.
Now we have seen in the earlier post that given a quantum coherent chi, then transitions that appears like miraclulos are easier to understand. Let me recap it mutasis-mutandis. Remembert that a sick state of say liver is given by constituent particles being at a given spatial and momenti configuration. So at sick state, particle p1,p2,p3,..etc forming the liver are at places x1,x2,x3,...etc respectively and have momenti m1,m2,m3,...etc respectivel. In the healthy state, they are at locations X1,X2,X3,...and with momenti,M1,M2,M3,...The transitioning from the small lattererd to the capitalized state is what we call 'healing'. If each of the particles p is a quantum particle, then the miraculous transition can happen at the 'colapse of wavefuntion'. But a group of a huge number of particles are often in a quantum-decoherent state at room temperature. So they dont manifest quantum behaviour. However, by weakly-interacting rather than strongly doing so, chi can circuvent this fate of quantum-decoherence that otherwise affect every other from of matter.
High temperature is due to particles having chaotic mixture of momentums of a wide range of values. A quantum-coherent state though must be of only a single momentum hence single wavelength due to deBroglie's hypothesis. So these two, temperature and coherence, don't go together. During observation, quantum states must interact with us. Since we must be warm, we must 'collapse' the quantum states. The 'collapse ' is the quantum-decoherence. But essentially what happens during 'transfer of temperature' from a warm body to a cooler body is exchange of momentum. Therefore electromagnetic interactions are needed for a given body to warm another body. This means that a weakly-interactin entity cannot undergo quantum-decoherence that is due to 'observation' by an ensemble of strongly-interacting particles like those forming our brain. This means that chi's quantum state cannot be easily destroyed by an interaction with our visible world.
But since chi cannot strongly interact with our charged bodies, a different way of explaining the change in momentum from m to M is necessary. This interaction will appear like a 'fifth force' capable of being decoupled at the will of chi practitioner in what can termed as 'top-down causation'. We still think of the change from m to M as just the usual exchange in momentum. So chi can circumvent all the wiggling of warm particles by not interacting strongly with our electromagnetism. The simple exchange of momentum to bring about M from m is not like the chaotic momentum that defines a warm state. Furthermore, the flux of chi also replaces the slightly decoherent one with the more coherent one. Hence chi must keep flowing litteraly to maintain its temperature just like the air does. This also may explain the 'fire of kundalini' due to 'blockage of chakra' etc.