Following a natural disaster, one can count on two things in the opinion pages and blogosphere: economists of all stripes decrying price-gouging legislation in a disaster and proponents calling economists immoral for questioning such legislation.
The conversation/disagreement between these two is a microcosm of a much larger discussion: the difference between the normative (subjective) and the positive (objective).
Economics is a positive science. It deals with what is, not what ought to be. When economists argue that price ceilings (like price-gouging legislation) cause shortages, that is a positive claim: it is a claim of what is. This claim can be empirically tested, but it does not reflect the moral positions or suppositions of the economist. In fact, the claim carries with it no moral implications whatsoever. The claim price-gouging legislation causes shortages carries with it no more or less moral weight than the claim the sky is blue.
Conversely, morality is a normative science. It deals with what ought to be, not what is. When moralists argue that raising prices during a disaster is immoral, that is a normative claim: it is a claim of what ought (not) to be. This claim cannot be empirically tested (although it can be tested to see if it falls into various moral criteria). It reflects the belief structure of the person making the claim. The claim raising prices during a disaster is bad carries with it no more or less empirical weight than the claim the sky is blue is good.
Allow me to elaborate, lest I give the mistaken impression that normative and positive sciences are opposed. Normative and positive are not opposed; in fact, they compliment each other quite well. Normative can prevent positive from becoming abusive (think, for example, our modern sensibilities against eugenic human breeding [normative] despite knowing certain traits are genetic [positive]). But positive can also keep normative from being “pie in the sky,” by explaining how the world is. For example, normative claims like “one should not kill his neighbor,” are all well and good, but the positive claim that “murder happens,” is important to know, too. Knowing the two together brings us to the conclusion that police are needed for the few who do break the law.
To apply this reasoning to disasters, knowing price-gouging legislation makes the logistical system worse is important to know, as it can help inform better forms of aid and legislation.
In short, answering a positive claim with a normative claim will get us nowhere, but the two must be given, and understood, concurrently.