Personally, I love discussing this thing about my character, who has many abilities that could be accurately referred to as "spectral."
There is no scientific explanation for how he switches between the physical and spiritual worlds - but "phasing" through a solid object does not, in reality, require magic or an innate unnatural ability.
It's been scientifically proven time and time again that when certain particles vibrate at a fast enough speed (typically a form of radiation), they are able to phsyically pass through most solid material.
Now, this might be deemed truly impractical by simply observing the speed at which particles similar to these - like light - travel. 299,792,458 meters PER SECOND. That's uber fast, in case you couldn't tell. I justify this with the kinetic theory, applying the same principles that apply to gases to the particles in Ethereal's body when he phases. The reason that gas spreads throughout the space which it is contained in (diffusion) is because its particles have much more kinetic energy than either liquids or solids. We're unable to tell when a gas might be particularly energetic based off of the sheer force with which these particles move, because it's simply too insignificant to feel. However, a gas particle, when contained, may move at great speeds without ever moving more than a few inches from its initial position. Therefore, when Ethereal phases, his atomic bonds take on especially strong properties that allow the radiation-like particles in his body to vibrate at unreal speeds without requiring a physical container. Since the elements that compose his scales and skin are not indigenous to Earth, there is no matching element in existence that shares these properties.
Please, challenge any weakness you find in this theory - honestly, I just refined it a great deal and am eager to go further if I have erred.
), and to me this sounds...er... sound. Of course, it is a little 'ow my brain', but yeah, all seems feasible.
All very interesting too. I like it when people use science to explain stuff, especially to do with dragons. All to often it's just waved away as 'yeah, magic does it'.