Gravity and the Soul

I read that proving the existence of the soul was like proving the existence of gravity, in the we can’t see gravity but we see the effect of gravity.

First of all we might see that someone called the cause of objects falling to earth gravity. I suppose before that we could say that gravity didn’t exist.

Things still acted the same, moved toward the earth, before Newton and the name he gave to the cause of the action. So is the action the effect of the name given to the cause?

What people want to attribute to what someone called the soul is not nearly as straightforward as these thoughts about gravity because first we’d need to decide on the effect, the actions we want to include… what would those be exactly?