Let the model find the features
For decades, the hard part of machine learning was feature engineering — a human deciding which measurements mattered before any learning began. Deep learning's breakthrough was to hand that job to the model. Give a deep neural network enough raw data and compute, and its layers discover useful representations on their own, each layer building on the one below.
Different shapes of network suit different data: convolutional networks for images and computer vision, and Transformers for language and sequences. The same family powers today's generative AI, from image generators to large language models.
What changed to make it work
The ideas are decades old; what unlocked them this century was the combination of large datasets, fast GPUs, and better training tricks — not a single new equation.
