This webpage (1) lays out the basic idea of positive or substantial freedom, (2) distinguishes it from negative freedom on the one side and happiness on the other, and (3) relates it to the notion of "capability," which is distinct from a raw capacity and an actual exercise of a capability.
This summary is mainly based on Amartya Sen's 1999 book, Development as Freedom (New York: Random House), hence DAF. At the bottom there is a link to information about Martha C. Nussbaum's extension of Prof. Sen's theory.
Sen's "perspective of [positive or, as he calls it "substantial"] freedom" is concerned with "enhancing the lives we lead and the freedoms we enjoy," in other words, "expanding the freedoms we have reason to value," so that our lives will be "richer and more unfettered" and we will be able to become "fuller social persons, exercising our own volitions [capacities for deliberate choice] and interacting with--and influencing--the world in which we live." (DAF, 14-15) In his view, positive freedom is "intrinsically important as the preeminent objective of development," that is, of public policy. (DAF, 37)
Public policy--the programs and rules by which government and other public agencies arrange our lives in society--is supposed to be the means by which human beings pursue what is good or ethically desirable in the public sphere. Perhaps it is not too much of a stretch to treat Sen's perspective as an ethical perspective that may also help us evaluate the interactions between people in families and other associations.
We should try to explain what Sen means by "substantial freedoms." Substantial freedoms are (1) valuable things that can be divided up and delivered to human beings (or groups of people in a region) in varying amounts. In that respect they are like money and freedom from coercion, things which can be preconditions for substantial freedom but are not very good indicators of it. In the case of money, a person can have very little, a middle amount, or a lot. In the case of freedom from coercion, the same can be said: one can be a slave, constantly subject to the whims of an overseer, or one can have maximum available freedom from coercion by one's fellow humans in their private or governmental capacities. What society does, and to some extent what individuals do, can determine how much substantial freedom we have.
But substantial freedom (2) has to be distinguished from other things that we "often have reason to value": money, negative freedom (aka negative liberty, or freedom from coercion), and happiness, on the other.
Thus it is often more effective, in the promotion of substantial freedom, to invest in public programs that will provide access to inexpensive health care or make neighborhoods safer places than to divide the money that would be used on these programs among the individual people who happen to be sick or who live in the affected neighborhoods.1
Substantial freedom is somewhere between negative liberty and well-being or happiness. Sen appears to believe that the more substantial freedom one has, the happier one is likely to be. But the correspondence between negative liberty and happiness is not so close. Yet negative liberty can be a precondition for substantial freedom. Thus, perhaps we have a scale
Substantial freedom differs from negative freedom in this way. A person who is without resources (a plot of land of her own to farm, seeds to plant, water to irrigate, education, access to health care, ability to pay for what she needs, powerful friends, etc.) may live a life that is unpleasant and short. But if she is not attacked or robbed by others or enslaved against her will, then her negative freedom is not violated. Yet we might forgive her for thinking that neither is her negative freedom worth very much to her. Substantial freedom, by contrast, provides people with real opportunities that negative freedom by itself does not.
But having a capability is not a guarantee of use. A person who can lift weights because she has practiced doing so still has this capability when he is asleep or reading a book and not lifting weights. (What makes it a capability and not a raw capacity is that she could move to activate it relatively quickly.)
There are important freedoms that have an instrumental role in making positive freedom possible. One of Sen's chief points as an economist is that we should not act as if there is just one of them. He lists five groups of instrumental freedoms:
political freedoms-- "the opportunities that people have to determine who should govern and on what principles, and also include the possibility to scrutinize and criticize authorities, to have freedom of political expression and an uncensored press, to enjoy the freedom to choose between different political parties, and so on. They include . . . opportunities of political dialogue, dissent and critique as well as voting rights and participatory selection of legislators and executives."
economic facilities— "the opportunities that individuals . . . enjoy to utilize economic resources for the purpose of consumption, or production, or exchange." The quantity of income as well as how it is distributed is important. Availability and access to finance are also crucial. (Not being able to get credit can be economically devastating.)
social opportunities--arrangements society makes for education, health care, etc.
transparency guarantees--these relate to the need for openness that people can anticipate; the freedom to deal with one another with a justified expectation of disclosure and clarity. These guarantees play a clear role in preventing corruption, financial irresponsibility, and violation of society's rules of conduct for government and business.
protective security--a social safety net that prevents sections of the population from being reduced to abject misery. Sen refers to "fixed institutional arrangements such as unemployment benefits and statutory income supplements to the indigent as well as ad hoc (temporary) arrangements such as famine relief or emergency public employment to generate income for destitutes."
1. Even if we broaden the notion of income to include other resources that might be distributed among individuals such as land, food, actually used services, etc. we have not quite captured the notion of substantial freedom. Other factors of a less easily divisible nature can make a difference. The mix of goods and services available in one's neighborhood and from among which one could choose if one wished, their accessibility in terms of geographical layout, makes a difference in one's substantial freedom. Another example would be a healthy (pollution-free) and biologically diverse natural environment. Not all preconditions of substantial freedom can easily be apportioned among individuals. They include public goods whose presence tends to increase the substantial freedom of individuals who live in a certain place.