For a mind without perceptions does karma exist??
Good and bad exists only when you perceive, e.g. people perceive this is right and that is wrong and live in illusion.
When a child without knowing playfully kills ants, does this create karma?
Paramhansa Yogananda described the mind as that part of us that perceives the reality we live in. So the mere fact that we have a mind also entails that we have perceptions. The mind, by its inherent nature, tends to see the separateness of everything, but it also helps us to distinguish between good and bad.
It is our consciousness that is truly the essence of who we are, with the mind expressing that consciousness. The more we open up to expanded consciousness through meditation, devotion, service, and attunement, the more we are able to neutralize the pulls of delusion.
Here’s a practical way to understand good and bad, or right and wrong: if something is leading us away from expanded consciousness, then it is harmful; on the other hand, if something is leading us towards expanded consciousness, then it is beneficial.
As to your question regarding karma if a child playfully kills ants: Yogananda said that in such instances there is still some karma that the child will accrue, but certainly not to the same extent if such an action is done with aggressive intent.
I hope this is helpful.
In divine friendship,