In a lengthy response to a hyperbolic, ill-informed opinion piece, Aaron Gustafson describes progressive enhancement:

It’s a philosophy that recognizes the nature of the Web as a medium and asks us to think about how to build products that are robust and capable of reaching as many potential customers as possible. It isn’t concerned with any particular technology, it simply asks that we look at each tool we use with a critical eye and consider both its benefits and drawbacks. And it’s certainly not anti-JavaScript.

I spent a good deal of time in 2015 writing and speaking on the benefits of this approach to designing and building for the Web:

• Designing Experience Layers
• In Defense of Progressive Enhancement
• The Practical Case for Progressive Enhancement
• Designing with Progressive Enhancement

The observant reader would note that Aaron and I address the same tenuous arguments made—coincidentally—by the same people.