What is Economics?

Jacob Viner is rumored to have said that "Economics is what economists do." This paragraph from the Economist suggests Viner is right now more than ever.

Economics has fragmented in the past 15-20 years, both in subject and technique. No aspect of human behaviour is off-limits and a miscellany of methods are in vogue, adding laboratory experiments, randomised trials and computer simulations to the traditionalist’s blackboard and chalk. Many of the brightest stars in economics parade their scepticism, insisting on how little economists really know (or indeed how little real economics they know). The discipline is more exciting, ingenious and intrepid as a result. But it is also unruly and untidy. Some economists are still patiently adding to a cairn of knowledge. Many are throwing rocks.

What do you think? Is there a core of economics that has remained largely undisturbed over the last 15-20 years? Is the miscellany of methods as widely accepted as the above paragraph suggests? And, if so, is it a passing fad or a paradigm shift?