seen the light

To see the light is to come to understand something that was previously unclear, or to experience a conversion in belief or attitude.

The phrase often implies a sudden realization or awakening, as if emerging from darkness into illumination.

Someone who has seen the light about a bad habit may finally quit; a skeptic who sees the light may become a true believer.

After years of resisting technology, my father finally saw the light and got a smartphone.