(For new reader and those who request 好友请求, please read my 公告栏 first).
Rawlsian Justice and Decision Theory  - 世界是公平的嗎?



– 决策论 与Rawl’s 公平哲学



The Late American philosopher, John Rawls, wrote a famous book entitled “A



theory of Justice” (Note added 5/24/2013: It should be emphasized that this aritcle is NOT a review or summary of Rawl's book but merely an explanation that one of Rawl's idea which provides a satisfactory resolution of the everyday question posed in the title and an explanation in terms of the lanquage of decision analysis) .   Not being a professional philosopher I cannot give an



authoritative explanation. However, the basic idea of justice John Rawls



espouses has an interesting connection with modern decision theory which I



do know something about. Furthermore, it has in my opinion a practical



interpretation to our everyday question “is the world fair?世界是公平的嗎? “.



I shall try my best to explain this to Science Net readers here.



On the surface, the world is not fair. Some people are born rich, smart,



and beautiful while others are born handicapped, have more than his share



of misfortunes in life.  Thus, we say “the world is not fair”. A simple



minded solution would say that let everyone be born in exactly the same



circumstance, endowed with the same ability, encounter the same events



throughout life, and finally die after the same number of years. But this



will make an extremely uninteresting and dull world. A bit more



interesting variation is for God to create a large number of EQUIVALENT



(meaning fair) situations for ANY happenings in a person’s life. Each



person will go through life encountering only one of the equivalent



situations for any event in his/her life. But this still makes a rather



uninteresting world even if God made it possible. Because basically,



everything in life is still more or less deterministic in this set up. You



know how many misfortunes you will have in your life and when they will



occur even though you may not know the nature of the misfortune except



that they will be equally unpleasant. Furthermore, what is unpleasant to



one person may not be to another. How is God going to make everything



equivalent? It is here Rawls came up with an interesting idea.



Let us suppose each person before being born has a number of choices. S/he



can be born beautiful, talented, live a long happy life, or other less



desirable choices, etc. etc. But, and this is a big “but”, if you choose



to be born and endowed with certain “desirable” traits, God will let you



encounter certain “undesirable” things and happenings  to balance things



out. On the other hand, if you choose to be born with



certain “undesirable” traits, you will be allowed more good fortunes later



on in the life. But wait, you will say, this still makes life rather



uninteresting. It is still deterministic. In a deterministic life why



should anyone “strive” for anything since everything is pre-ordained. And



you still have not solve the problem of different “equivalence” by



different people. It is here Rawls borrows some decision theoretic ideas



to make things interesting.



The basic idea in decision theory is the elementary lottery. In this

lottery, you are faced with a chance to win say 1,000 dollars with probability

p or nothing with probability 1-p. You are also given another choice of

getting 100 dollars for certain. Do you decide to choose the certain 100 dollars or the

lottery. A basic assumption of decision theory is that everyone has a value

for the probability p for which s/he will be indifferent between the two

choices. (If your are risk neutral, then the value of “p” for which you

will be indifferent should be 0.1)  In general , this value for “p” will

be different for different person depending on their attitude towards risk

and can represent the “utility” of the "lottery" for that person. This device

of making a certain event (receiving 100) equivalent to an uncertain

event (getting 1,000 or nothing depending on the outcome of a random

happening with probability “p”) is the basic element of making decision

under uncertainty in decision analysis. One can show that in a finite

world, any decision involving uncertainty no matter how complicated can in

principle be reduced to the choice between an  elementary lottery as above

vs. a certain  choice. The correct and optimal decision will then be

obvious. The problem of course is that this reduction is in principle. In

practice, often it is computationally impossible either because lack of

data or the calculation burden. The point is that decision analysis deal

with HOW to make good decisions and not with guaranteeing good outcomes.

You may choose the lottery and end up with nothing even though the value

of “p” may be very favorable.



Using the above idea Rawls declares that in an ideal and FAIR world, if you

were given a chance to choose what kind of life you may have in this world

and there are infinite number of possible lives each with all kinds of

uncertainties , then you will be indifferent to all the choices.  There is

an old Chinese saying of 红颜薄命, that is,  if you are born beautiful,

then you will have a miserable life. However, Rawls goes one step further.

He says that if you want to be born beautiful, then the probability of

your having a miserable life will be high. But if you are really lucky,

you may actually have a good life. You would  not know the actual outcome

when you choose to be born beautiful, only the probability. Against this

uncertainty with a given probability, you may decide to choose to be

born “plain”. And at some value of “p” you will be indifferent between the

two choices since they will appear equally desirable or undesirable. In a

fair Rawlsian world, your choice will be indifferent among all the real

life choices. Note here the actual life (i.e., the outcome) you live after

your choice may be very different for different people because of all the

uncertainties.  But if you have infinite computational power at your

disposal, you can use decision theory to analyze all the choices in

principle. In a world that is just and fair, you will find all the choices

equally good or bad a priori. But because of uncertainties, your actual

life outcome will not be known beforehand. This makes life interesting and

worth living even in this world.  And you may say this is a sophisticated

and the ultimate realization of the ideal embodied in the American

Declaration of Independence that “all men are created equal”.

Of course, ideal world does not exist. Society and government are organized

to help the world be fair and just. Thus, we have welfare (福利) and

charity to help the less fortunate; we have the saying “能者多勞” to let

the talented bear more of the burden; and the old to help the young, etc



and etc. they are merely our imperfect attempt at justice.

An understanding of the philosophy of Rawls and decision theory  permits us

to view the injustices in the world in a deeper sense,  give us incentives

for our individual and societal obligations to make the world more fair,

do our best with what we are given, and hopes for the future.