Fuel

All life forms require fuel.  Same goes for human-made machines.  

Machines only run on specific kinds of fuel:  gasoline, firewood, natural gas, coal, electricity, sunlight, wind, etc.  Machines quit functioning when their fuel supply is depleted.  When the electricity stops, the ceiling fan quits turning.  When the natural gas quits flowing, the furnace stops heating.  When the gas tank is empty, the car engine quits running.  

For the most part, machines run only on the fuel they were designed for.  We can try if we want, but lawn mowers don't run if we put coal in the gas tank.  We can try if we want (and some have), but a gasoline engine won't run (for long) if we put diesel in it.  We can try if we want, but the coal-fired ship engine won't operate if we try to fuel it with sunlight. 

We humans are fundamentally three dimensional beings:  physical, intellectual, and spiritual/emotional.  Each of those dimensions runs optimally on certain kinds of fuel.

Some fairly important questions follow:  

1. What kind of fuel does our physical body need for optimal performance? 
2.  What kind of fuel does our mind need for optimal performance? 
3.  What kind of fuel does our spiritual being need for optimal performance? 

Oh, one more question:  What kinds of fuel have we been supplying for each?