Dagdha dahana nyāyaḥ (burning the burnt)
The fire can not burn anymore that what is already incinerated.
The common sense of this is clear. There is no meaning to perform fruitless work or execute that what already was executed. Yet men attempt this vainly, in a sense getting a quality and permanent happiness from dead matter, which is fruitless work with much labor, or stealing, and imitating the works and ideas of that what has been already done. The best example of this is the existence of this material world. This world is already created by God, yet we always claim the credit for all the petty things we recreated from God's energy, using God's given hands and legs, and using God's given intelligence or stupidity, whatever may be the case. So we exercise our vanity. The dogs are barking since the time they are dogs, annoying everybody around. But if a man imitate the barking of the dogs, the people will pay gladly to see this imitation of that what is already done in nature. Similarly, if scientists imitators just promise, not even create, just promise that they will create a life in laboratory, they will receive many millions of dollars just for a promise of needless outcome. However, they have been already overrun by most prominent scientist, the God Himslef. He invested this capability to create the life in all the living entities. Since the beginning of creation, they know how to do it without PhDs, commonly by uniting male and female.