What are the differences between sculpting and proportional editing? They seem superficially similar to me.
Yes, in basic terms they perform the same task.
Proportional editing is a more technical method. You select specific vertices and move them with the surrounding vertices also being moved based on the choice of a preset curve.
While sculpting deforms the vertices in a similar way, the user gets a more artistic approach to what part of the mesh moves. Brush strokes are a much quicker, dynamic way of selecting which vertices get moved.
Additionally, sculpting offers the ability to define the falloff curve or use an image to define how the surrounding vertices are moved, which s not possible with proportial editing. This gives sculpting a way to model shapes on the surface of a mesh much faster than you can do manually. The trade off (particularly with dynamic topology) is you don't have control over the topology, so you can just as quickly get a messy looking mesh.
Sculpting has dynamic topology which means you create more vertices as you sculpt. Proportional editing, while similar to sculpting without dynamic topology, has the benefit of being extremely exact as you can drag vertices, edges, and faces directly along the xyz axis or rotate a specific amount. Proportional editing also has fall off options which makes modelling very easy. The random fall gives incredibly interesting and varied results.