Edith Efron's article ("Behind the Cancer Terror," May) claims that the proof of a negative is impossible in logic. Such a statement is wrong. More than 2,000 years ago the Greeks proved negative statements: Euclid proved that the number of prime numbers is not finite, and Pythagoras proved that the square root of two is not rational. As a matter of fact, if one could prove that a person can not prove a negative in logic, that proof, in itself, would be the proof of a negative.
Charles R. Burton San Diego, CA
Senior Editor Machan replies: Negatives can be proven, of course, in several ways: by disproving the affirmative, by showing that the affirmative is without meaning, by showing that the affirmative is self-contradictory. What confuses many is that, usually, affirmative statements can be changed to negative ones (she is well/she is not ill) without much loss of meaning or precision. But in problematic, novel propositions-the ones that interest scientists-we are unable to prove a negative unless its corresponding affirmative is provided with some attempted justification. This is why in our courts of law, for instance, the prosecution has the onus of proof-to place on record an affirmative statement (x did y), which then may be challenged by the defense by showing it to be unfounded and thus disproving it. In science, too, unless a case is advanced for the existence of some property or condition or correlation, it is impossible to know what must be done to test the affirmative case; it might require canvassing the entire universe to make sure that one hasn't missed some possible (unstated by the affirmative side) interpretation of the proposition at issue. And in this sense-that is, without a case for the affirmative-it is indeed impossible to prove a negative.
While I enjoyed Eric Mack's presentation of alternative national defense methods ("The Perils of Pacifism," Viewpoint, May), I believe Professor Mack is exactly wrong in making pacifism the antithetical equal to militarism as an "extreme" forcing mankind to "bow before evil."
Mack states that pacifism is incoherent since the ideology "den(ies) that we could have a right to defend our lives and liberties." This is correct, but only if the professor limits such a defense to violent acts. This is precisely what the Reagan administration is doing in Central America, for example, when a far better way of ensuring democratic liberties there and protecting Americans here would be for the United States to pull its military and mercenary forces out of the region and allow the Contadora group to negotiate the pacification of Central America that they are now so close to achieving.
Dialogue may not be the only way to disarm our myriad enemies throughout the world, but I would wager that even Professor Mack would agree that far too much of our national security debate is taken with military "defense" rather than reestablishing a credible diplomatic offense. It is odd that he would feel compelled to misrepresent the very ideology whose goals he is, after all, aspiring toward in urging more responsible methods of national protection.
Alexander Reyes, Washington, DC
Mr. Mack replies: Alexander Reyes points out that defense in the sense of the responsive use of destructive force is not always necessary for, or well-suited to, securing rights. This is certainly true and deserves emphasis. Destructive force is only justified when no other means are available. Contrary to Reyes's reading, however, my remarks about strategic defense in no way imply approval of the current US military intervention in Central America. This intervention seems: (1) not directed against a threat to our rights; (2) likely to be counterproductive by its own lights; and (3) immorally supportive of various bands of thieves and murderers.
Counsel for Coors
I read with great interest Kelly Ross's article on Coors's battle with the Oregon legislature ("Brewed-Up Boycott," March), but I was surprised that Coors hasn't asked the courts for some help. The Oregon legislation places a serious burden on interstate commerce. In such cases courts are required to balance the effectiveness of the state statute in accomplishing valid state interests (such as health and safety) with the burden the statute places on interstate commerce. If the statute doesn't effectively promote those interests and yet burdens interstate commerce, the legislation must fail.
Further, the US Supreme Court has recently been backing away from allowing states the broad discretion with respect to liquor granted them under the Twenty-first Amendment when such latitude would infringe on other Constitutional guarantees. Coors also might argue that the legislation has nothing to do with the alcoholic nature of the beer but rather with the health of the public in general and, therefore, the Twenty-first Amendment does not apply.
From this it seems that Coors has a fighting chance to challenge this law and clear the way for fair competition. It's nice to know that there is some protection left from legislatures gone special-interest-happy.
Michele Berdinis Berkeley, CA