Common Patrimony

Following John Locke, we can view the stock of the planet's material resources as humankind's "common patrimony" that is commonly held by all people in all generations.  Passing it along to our descendants is an obligation, just as is the passing of private patrimony is within families.

From Locke's foundational idea, Edity Brown Weiss (1) has derived this principle governing obligations to future genaerations:
 

From now on, forebears must leave for descendants this single, indivisible stock of global resources (or at least the options for certain key human activity which these resources provide) that is:

 a) as much
 b) as good
 c) as accessible

as the block of resources or options previous forebears had available.

1) by replenishing those materials that can be replenished
2) by finding alternative means to achieve the activities for those materials which can't be replenished
3) by leaving certain things completely intact - air, habitats, ecological capital

A) Because failure to do so would be:

 1) unfair
 2) inequitable (equitability = sameness of treatement)
 3) unjustifiable (we can't develop criteria for why one generation 'deserves' more of the common block than others, and thus it must be indivisible and held by all generations equally.)

B) Fairness is defined as those principles for distribution which would be agreeable to all people in all generations (if in Rawl's hypothetical Original Position - see below), ie, if:

a) we knew the circumstances of scarcity
b) but we didn't know what generation we would be in

(1) Weiss, Edith Brown (1989).  In fairness to future generations: International law, common patrimony, and intergenerational equity. Dobbs Ferry, N.Y. : Transnational Publishers/
 

Rawls' "original position" and "veil of ignorance"
American political philosopher John Rawls (A Theory of Justice, 1971, Harvard U. Press) developed the hypothetical concept of the "veil of ignorance" to describe the "original position" from which a rational and self-interested person should proceed in developing the specifics of collective arrangements in society.  To explain:  Assume that humans have responsibility for their collective social, political and economic relations. How should we then go about designing a system (and by extension, reforming the present system) which is just?  Rawls says, to do this, you must imagine yourself behind a "veil of ignorance" with regards to the specifics of the position you might be born into.  So, you don't know your race, gender, class, handicaps, appearance, or any other specific which could determine your particular opportunities in society. From that position, you as a rational self-interested person, might reasonably fear the worst -- or at least want to cover for the worst possible scenario. So you would set up society so with special protections so that if you should happen to be "disadvantaged," you would not suffer for it.  Among the conditions one should be ignorant of in this thought-exercise is the generation of human occupants of the earth into which you were born, since that might determine the health and richness of the environment you inhabit, and thus many possible opportunities and costs.  If you were born early, at a time of plentiful resources, that would be good for you. But you should fear being born late.  Thus, you would choose to set up society along the lines suggested above: you would institute systems that would ensure later generations access to common patrimony of the earth, and the opportunities it affords.
 
 

More on obligations to future generations

Some argue for weak obigations, others for strong ones.  Below are some of the aspects of these arguments, and things they emphasize

WEAK OBLIGATIONS TO FUTURE GENERATIONS

-typically reflect libertarian individualist values
-stress risk of injustice to contemporaries in name of future persons
-hold that rights derive only from strict reciprocity of self-interested parties; rights cannot be possessed by "possible" persons
-stress that the plasticity of human behavior means we are ignorant of the characteristics (and thus needs) of future generations
-Feel that obligations must be qualified by:

-partial & uncertain knowledge
-real indeterminacy of outcome

STRONG OBLIGATIONS TO FUTURE GENERATIONS

-note that nature and existence of future society is dependent on present choices, policies, actions
-counter the above argument about rights by noting that moral community is composed not by contract but by common social ideal
-inevitably we determine circumstances of the future; we must plan for them
-argue that there are human universals; human nature is not all that plastic
-critiques dominant values
-has reservations about technological competency - many costs, qualifications & exceptions to the benefits of technology
-accept that heroic sacrifices may be demanded of the present once our obligations to the future are taken seriously