Viability is often used by pro-choice advocates as a tool for establishing when the unborn child should be considered a person with legal rights and protections, and it is a principle that is widely used in society as a basis for law when it comes to abortion.
For such a prevalent basis for policy, it has always surprised me that the relevance of viability is so rarely explored. Viability is basically the point at which the unborn child becomes capable of surviving on its own outside the womb if given up-to-date medical treatment. To some, this capacity for independent survival is a good place to distinguish the unborn child as a separate person, but the more we try to apply the concept the more problems begin to crop up.
The first issue that I think many people will note is that viability itself is little more than a measurement of medical technology, rather than any quality or trait inherent to the child. As time goes on, we have been able to keep kids alive at younger and younger ages, and in principle, eventually, the unborn child may be deliverable at any time, perhaps even from fertilization.(1)