The common way of thinking about a legislature is that it enacts laws that are just. That which is in the eyes of the population "bad" is outlawed and what is "good" is kept legal. That's a model that has been with us since antiquity. Of course, in the old days the law came from the God(s) but the point was the same -- differentiate between right and wrong.

Experimental governance brings in a completely new way of thinking (+). The legislature is instead seen as an experimenter and laws are seen as tools to use to regulate the behavior of the populace. Maybe the government identifies X as a problem, so a temporary law A to combat the problem is drafted. The law is enacted but with a provision so that it expires after say an evaluation period of 18 months. Then the government studies what effects the law had. If the negatives outweighs the positives, maybe try law B instead and the process repeats itself.

The advantages to experimental governance is that laws can be enacted quickly and in response to changing circumstances. And that "beta testing" makes it easier to write tighter laws free of loop-holes and other problems. Disadvantages include: 1) Regimes can abuse the system by extending quickly drafted temporary laws indefinitely (e.g Patriot Act). 2) If there are no checks and balances built into the system, arbitrary or contradictory laws can be enacted. 3) If the population isn't following the political debate, it might not be aware of what the law is. Thus, EG works best in stable democracies with educated populations, like the EU countries where it is used extensively.

+ Of course no idea is 100 % new, but I know of no similar historical precedent. Temporary laws and decrees have been used in the past, but afaik they have always been considered aberrations and not "natural parts of the system."