As the seat of feeling it feels dreadful when the favourite political party loses the election, yet feels nothing at all when God is dishonoured. Recall how you felt the last time you were slighted. Likely you felt nothing. The heart is also the seat of thought and understanding. In fallen humankind thinking, then, is distorted too.
Fallen humankind remains able to do algebra marvellously.
Rather it's the case that our thinking serves the wrong end. Not that we can't perform electronic wizardry, but that we deploy electronic surveillance and super-sophisticated munitions and thereby dehumanize ourselves. For our Hebrew foreparents the heart is also the seat of the will. Our will is our doing. No child has to be taught to misbehave.