Hello Sanderson fan's .As you can tell I am new to this forum.It has been few months seen i started reading Sanderson's work.I loved it so much that I started rereading some of his works in order to understand some things better or to see things which i might have overlooked initially.
So I have a theory on how i think magic is fuelled by things that are some what related to five human sense organ,I hope this is the right place to post this and here is my theory.
First in Mistborn the magic system Allomancy and Hemalurgy is fuelled by substances which is ingested through mouth,You ingest a metal in your body and burn it to fuel your magic.As long as you have the metal you can use your magic.This could be related as a magic system which is fuelled by something you eat or drink through your mouth,one of the sense organ.
Next the Feruchemy is fuelled by substances which touches your body.The metal charge are fuelling your magic as long as they are touching you.This can be related to a magic system which is fuelled by something that you can touch with your skin.Another of sense organ.
Third in storm light archive the surgebinding is fuelled by stormlight which is breathed in to the body.You can perform surgebinding as long as you have stormlight.I suppose it is breathed in through nose .Another sense organ.
Above three are pretty direct way of explaining it but now it get some what difficult.
Fourthly in Warbreaker the Awekaning is fuelled by breath and color around you.Breath gives you enhance vision,You see things better an more saturated i suppose.You use your breath to awaken object which cause the surrounding to loose color and also reduces your vision capabilities.So it can be explained as a magic system which is fuelled by something that you see with your eyes (the color), another sense organ.Although it is called breath but you are using your strength of vision to fuel the magic system.
I am not sure of Sel's magic system as i know very little of it and it has been a long time since i actually read Elantris .(Actually it is not that long but I read it during the start of my cosmere days and after that i have read so many other things that i almost do not remember much of its magic system.)Also i haven't read any of the short stories or unpublished cosmere works yet so i cannot comment or provide explanation for such magic system.
Now you might say that only sense organ that is left is ear.A magic system that is fuelled by something which we hear.This whole theory struck me when i was reading or rather rereading TWOK,the particular intersection between Hoid and Kaladin where he gives him a flute and tells him to learn how to use one.In that chapter many believes Hoid is using some form of magic which causes Kaladin to see things in the smoke created by fire.So hoid was playing the flute.What if he was using a magic system that was fuelled by music or sound from the flute?Hoid has been seen carrying musical instruments around maybe he is able to use said magic system which is fuelled by sound or it has got something to do with sense of hearing.
Now another of most asked question of cosmere is why did Vin avoid Hoid?
She found him humming to himself.Maybe he was using some form of magic system fuelled by sound from his humming and Vin saw it through her bronze burning but since Hoid was not using allomancy she could not recognize the magic system as bronze burning would recognize allomancy.That something about Hoid which bothered Vin might have been her bronze warning her of another form of magic.
Well I found above concept interesting and thought i should share it with you people.Now there are few exceptions as well.
Lift is able to use surge binding by fuelling it from eating food.Using mouth instead of nose for taking in the fuel.Only explanation i can think of is that she has half of her body in shadesmar allowing her to intake fuel in more that one way.
Also Vin was able to draw upon the mist .I suppose she breaths in the mist.Using nose to take in the fuel instead of mouth.She was also holding a shard at that time so maybe she also had access to shadesmar allowing her to intake fuel in more than one ways?Not sure about this one. i will had to re read Mistborn.
So that is my thoery .Hope I am not forgetting anything .Please do correct me if i am wrong in any places and let me know what do you think of the theory.