Yes, you need data. But the amount depends on your task, and there are pretty significant sources of large amounts of data available online.
For example I was at a presentation where a person built a pretty interesting neural model based on 190k clinical records released via Kaggle. In most fields it is surprising how much data is easily accessible.
For example I was at a presentation where a person built a pretty interesting neural model based on 190k clinical records released via Kaggle. In most fields it is surprising how much data is easily accessible.