Sleeppy
Fatalist. Christian. Pacifist.
They rot, and you don't really need data, simple observation will tell you this every time.
In this case, you do. What scientifically, is the physical decay process? Decay describes a rearranging of physical material. Energy is released and redistributed.
We actually decay regularly. We die, regularly. We release, intake, and transform energy incessantly. You aren't the same as you were at any other moment in time, but not wholly different either. Etc. Etc.
Is simple observation enough for beings of limited perceptive ability, to find truth? Only through time, and trial and error.