Pro-life apologist extraordinaire, Scott Klusendorf, has written an excellent post today on the topic of why so many Americans have a hard time grasping the humanity and moral quality of human embryos.  In brief, it is because they see human beings as things that are constructed rather than formed.  To quote Klusendorf:

Most people think an embryo is constructed piece by piece rather than something that develops from within. Consider a car, for example. When does the car come to be? Some might say it’s when the body is welded to the frame, giving the appearance of a vehicle. Others insist there can be no car until the engine and transmission are installed, thus enabling the car to move. Others still point to the addition of wheels, without which a vehicle cannot make functional contact with the road.

But no one argues the car is there from the very beginning, as, for example, when the first two metal plates are welded together. After all, those same metal plates can be used to construct some other object like a boat or plane. Only gradually does the assemblage of random parts result in the construction of a car.

…[M]ost Americans see the fetus exactly the same way-as something that’s constructed part by part. It’s precisely this understanding…that renders pro-life arguments absurd to so many people. As they see it, embryos are no more human beings in early stages of their construction than metal plates are cars in the early stages of theirs.

…

[T]he construction analogy is deeply flawed. Embryos aren’t constructed piece by piece from the outside; they develop themselves from within. That is to say, they do something no constructed thing could ever do: They direct their own internal growth and maturation-and this entails continuity of being. Unlike cars, developing embryos have no outside builder. They’re all there just as soon as growth begins from within. In short, living organisms define and form themselves.

Unlike cars, then, human embryos are human from the onset of development, not at the terminus of development (or any other point along the way).  In fact, if they weren’t human at the beginning, they could not develop themselves in a human fashion throughout the process.  I think this distinction between construction and development is a powerful and important point to incorporate into our pro-life apologetic.