Pro-choice advocates who justify abortion based on degreed properties step into a very tenuous field of landmines. For if an individual gains their value and rights based on degreed properties, then our value is degreed. Some humans deserve more respect and rights than others. In fact, some humans (fetuses) are so lacking in particular degreed properties, that we have the right to take their lives.
Beyond the undermining of certain human rights for particular groups, embracing degreed properties is problematic even further in that it is unclear at what degree rights should be conferred. Who gets to judge the level of intellect, size, or productivity that grants an individual their rights? Furthermore, who gets to judge which degreed properties are irrelevant to the consideration of rights? If a fetus can be killed because it hasn't yet developed certain abilities, why can't we kill others who have failed to develop (or who have lost) certain abilities (the blind, the deaf, etc)? Why does a degreed property like consciousness go into the equation of right conferral, but the degreed property of vision or the senses don’t? Basing human rights on degreed properties makes those in power the arbiters and definers of rights and value. Who can say that their arbitration is wrong and on what grounds?
With this more detailed evaluation of the common pro-choice problem, I would like to point out two other pro-choice arguments built on degreed properties: consciousness and personhood.
Consciousness: Some argue that a fetus does not yet have the right to life because they are not yet conscious. That a fetus is not conscious for a portion of its existence seems indisputable. But that consciousness determines rights and value is far from clear.
First, consciousness is an attribute which can be held in degrees. A fetus is less conscious than a four month old, and a four month old less so than a toddler. Even some adults with certain disabilities or injuries (permanent or temporary) are less conscious than others. If consciousness confers value and rights, then at certain times in all our lives we had less value than we now have, and there were/are times in our lives when some animals were/are more valuable than us.
Even if we assume that the mere presence of consciousness conferred value, and not any degree of it, we still run into problems. There are times in our lives when we are unconscious (sleeping, knocked out, etc), or perhaps placed in an induced coma, yet we believe we retain our rights and value. To argue that our value exists during these moments because we have a reasonable belief consciousness will return in the future is to undercut this argument's basis for denying rights and value to the unborn.
Finally, if one wants to continue arguing that the mere existence of consciousness confers value and rights, then we must confer value and rights upon anything that has the remotest semblance of consciousness. If one argues that mere consciousness confers rights and values in order to avoid the problem of degreed properties, this means many animals (crows, parrots, cats, etc) should be afforded the same rights and value as humans. Such a thing seems absurd, that I should spend life in prison if I kill a crow because the existence of a consciousness within it confers the same rights to him as it does to me. The argument from consciousness cannot be sustained.
Another option pro-choice advocates have embraced is the personhood argument. It is argued that a fetus doesn't have a right to life until it becomes a person. Such an argument runs aground on all the same problems as the argument from consciousness (it's degreed, one can gain and lose value and rights at various times in their life, some animals are more valuable than some people, and defining how much personhood confers rights is arbitrary). However, the argument from personhood has one other problem, which is its ambiguous and arbitrary definition.
Personhood, as I've seen argued, isn't really its own quality, but rather a conglomeration of qualities. Some of the qualities argued for creating personhood are metacognition (self-awareness), desires, the ability to plan for the future, etc. Requiring a number of degreed properties in order to assign rights and value simply exacerbates the problem, it doesn't solve it. Who determines that these specific sets of attributes confer rights? Who determines the degree necessary?
It's always unsettling when value and rights are determined and defined not by that which is objective and inalienable, but by that which the ruling class defines. One only needs to take a cursory glance at history to see how indigenous peoples, outcasts, heretics, the handicapped, and those who were deemed societal and economic hindrances have been treated in times and places where value and rights have been defined and quantified rather than observed and recognized.
1. The Foundational Question: What is killed in abortion?
2. How to Determine Value and Rights: What quality and types of qualities confer rights and value to an individual?
3. Justified Reasons for Taking Human Life: What justifies the taking of human life?
4. Unjustified Reasons for Taking Life: What reasons fail to justify the taking of human life?
5. Bad Christian Arguments and Witness: Common pro-life/Christian arguments and actions which can undermine the pro-life position.
6. Counterrebuttals: A response to significant objections to the pro-life arguments.