By Sherry Ackerman
I taught college logic for decades. Logical fallacies make me squirm. However, most people have errant ideas about logic. My undergraduate students always get huffy and insist that their ‘true premise’ is ‘logical’.
Logic examines process, prior to truth. A true conclusion can be arrived at if, and only if, the premises are true, and the process by which the argument is constructed is valid. Herein lies the rub. Most people are so attached to the ‘truth’ of their purported premise that they never subject it to the test of process. Thus, validity is never established. In logic, true premises, in and of themselves, do not constitute truth. They only contribute to a search for truth if they are participate in well-constructed arguments that are valid.
About now, most of my undergraduate students start jumping up and down, insisting that ‘whatever’ is true. They can’t listen. They can’t distance themselves from their assertion. They can’t entertain a counter-position, even for the sake of academia. They get antsy and run out of the room. And, thus, they can’t subject their claims to tests of process in order to determine validity.
Let’s look at an example. Everyone’s eyes are on the economy and the environment these days. Both are volatile and, therefore, have our attention. We hear statements like, “I am ‘for’ the economy” even if it means wrecking havoc with the environment. And, we hear counter-statements like, “I am ‘for’ the environment” even if it means economic decline. When these two camps convene, the fur usually flies. And, the whole scenario represents a formal logical fallacy, that of the non-exclusive disjunct.
The fallacy lies in concluding that one disjunct (premise) must be false because the other disjunct (premise) is true; whereas in fact they may both be true because "or" can be defined inclusively rather than exclusively. This fallacy is committed when making the false assumption that when presented with an either/or possibility, that if one of the options is true, the other one must necessarily be false. 
Our example of the counter premises between economy and environment is a perfect example, as they are most definitively not exclusive disjuncts. But, understanding their inclusivity takes a bit of revisioning our ideas about the relationship potential between ‘economy’ and ‘environment’.
A practical example of an inclusive relationship between ‘economy’ and ‘environment’ is found in a common conception about organic agriculture – that it sacrifices productivity and, thus, economic prosperity, in the interest of the environment. In Sacred Economics, Charles Eisenstein cites research showing that when it is done properly, contemporary permaculture methods, which are environmentally sound, can actually deliver many times more yield, and therefore greater economic boon, than conventional farming.
Another example can be found in the State of Vermont’s environmental and economic standards. Vermont is inarguably one of the most environmentally oriented, and regulated, States in the US. Its rigorous green policies have kept the Green Mountain State just that—green.
And, simultaneously, the Green Mountain State’s poverty rate is among the lowest in the nation, with a per capita income that is 19th in the Country and a rate of growth at 13th. Ice the cake with the fact that their rate of income inequality is one of the lowest in the Country.
These are only two examples, of which there are many, of ways that economic and environmental interests can be commingled—and where the non-exclusivity of the disjuncts of ‘economy’ and ‘environment’ are quite clear. The economy and the environment do not have to be pitted against one another. That is old, fallacious thinking that is worn out. There are abundant new ideas about ways in which they can work together, harmoniously, toward a more integrated, holistic quality of life.

By Sherry Ackerman I taught college logic for decades. Logical fallacies make me squirm. However, most people have errant ideas about logic. My undergraduate students always get huffy and insist that their ‘true premise’ is ‘logical’. Logic examines process, prior to truth. A true conclusion can be arrived at if, and only if, the premises are true, and the process by which the argument is constructed is valid. Herein lies the rub. Most people are so attached to the ‘truth’ of their purported premise that they never subject it to the test of process. Thus, validity is never established. In logic, true premises, in and of themselves, do not constitute truth. They only contribute to a search for truth if they are participate in well-constructed arguments that are valid. About now, most of my undergraduate students start jumping up and down, insisting that ‘whatever’ is true. They can’t listen. They can’t distance themselves from their assertion. They can’t entertain a counter-position, even for the sake of academia. They get antsy and run out of the room. And, thus, they can’t subject their claims to tests of process in order to determine validity. Let’s look at an example. Everyone’s eyes are on the economy and the environment these days. Both are volatile and, therefore, have our attention. We hear statements like, “I am ‘for’ the economy” even if it means wrecking havoc with the environment. And, we hear counter-statements like, “I am ‘for’ the environment” even if it means economic decline. When these two camps convene, the fur usually flies. And, the whole scenario represents a formal logical fallacy, that of the non-exclusive disjunct. The fallacy lies in concluding that one disjunct (premise) must be false because the other disjunct (premise) is true; whereas in fact they may both be true because "or" can be defined inclusively rather than exclusively. This fallacy is committed when making the false assumption that when presented with an either/or possibility, that if one of the options is true, the other one must necessarily be false.  Our example of the counter premises between economy and environment is a perfect example, as they are most definitively not exclusive disjuncts. But, understanding their inclusivity takes a bit of revisioning our ideas about the relationship potential between ‘economy’ and ‘environment’. A practical example of an inclusive relationship between ‘economy’ and ‘environment’ is found in a common conception about organic agriculture – that it sacrifices productivity and, thus, economic prosperity, in the interest of the environment. In Sacred Economics, Charles Eisenstein cites research showing that when it is done properly, contemporary permaculture methods, which are environmentally sound, can actually deliver many times more yield, and therefore greater economic boon, than conventional farming. Another example can be found in the State of Vermont’s environmental and economic standards. Vermont is inarguably one of the most environmentally oriented, and regulated, States in the US. Its rigorous green policies have kept the Green Mountain State just that—green. And, simultaneously, the Green Mountain State’s poverty rate is among the lowest in the nation, with a per capita income that is 19th in the Country and a rate of growth at 13th. Ice the cake with the fact that their rate of income inequality is one of the lowest in the Country. These are only two examples, of which there are many, of ways that economic and environmental interests can be commingled—and where the non-exclusivity of the disjuncts of ‘economy’ and ‘environment’ are quite clear. The economy and the environment do not have to be pitted against one another. That is old, fallacious thinking that is worn out. There are abundant new ideas about ways in which they can work together, harmoniously, toward a more integrated, holistic quality of life.