Many present-day bioethical arguments, although intellectually fashionable and trendy, nevertheless remain flawed in their reasoning. An impressive example of this can be seen in a recent Boston Globe article by professor Michael Sandel, who teaches at Harvard. He begins with a reasonable analogy between acorns and embryos, but quickly confuses his terms and ultimately draws an incorrect conclusion:

“...although every oak tree was once an acorn, it does not follow that acorns are oak trees, or that I should treat the loss of an acorn eaten by a squirrel in my front yard as the same kind of loss as the death of an oak tree felled by a storm. Despite their developmental continuity, acorns and oak trees differ. So do human embryos and human beings, and in the same way. Just as acorns are potential oaks, human embryos are potential human beings.”

The error in this passage can be summarized simply: embryos are not potential human beings; rather, they are human beings with potential. Embryos are potential taxpayers, potential pianists and potential bank robbers, but the only reason they have all that remarkable potential (and so much more besides) is because of what they already are, namely, human beings.

Acorns, of course, become trees, even though an acorn is not itself a mature tree. The acorn and the mature tree, however, are both “oak,” and the acorn is just a younger version of the mature tree -- the two are different developmental stages of the same oak. Therefore, acorns are not potential oaks; instead, they are actual oaks with the potential to become mature trees with branches and leaves. Embryos, similarly, produce adults, even though an embryo is not itself an adult. The embryo and the adult, however, are both “beings that are human,” and the embryo is just a younger version of the adult -- the two, in fact, are different developmental stages of the same human being. Hence embryos are NOT potential human beings; rather, they are actual human beings with the potential to become adults with arms, legs and checking accounts.

Do we treat the loss of an acorn eaten by a squirrel in the front yard as the same kind of loss as the death of an oak tree felled by a storm? We don’t treat them the same, because in the case of the felled tree, with its large dimensions, we need a chain saw to clear the debris, while in the case of the acorn, no chain saw is required. Additionally, we are not likely to have much emotional attachment to a little acorn, while we might have strong attachments to the large tree that has been in our front yard for years. But feelings and emotional attachments don’t alter the fact that the loss is the same kind in both cases -- the loss of an oak -- a very little oak in one case, and a very big oak in the other. Because we may become emotionally attached to a big tree, we can slip into mistakenly supposing that the acorn is not an oak. Regardless of whether we might have a personal bias or an emotional attachment to a big oak, or even a prejudice against little oaks, our prejudice cannot alter the hard biological fact that both the acorn and the mature tree are oak. Similarly, by becoming emotionally attached to grown-up human beings, we can slip into mistakenly supposing that an embryo is not a human being. Yet any emotional response or prejudice we may have regarding human embryos cannot change the hard biological fact that both embryos, and the taxpayers they grow into, are human beings.

Sometimes the acorn analogy is taken one step further, in an attempt to suggest that human embryos do not become human beings until they implant into the uterus. The argument runs like this: an embryo is like an acorn that has not yet been planted in the soil. That acorn is only a potential oak tree, not an actual oak tree. It will become an actual oak tree only after it is planted and grows, and the human embryo will become a human being only after it implants into the uterus and begins to grow. While it is true that acorns don’t become mature trees until after they are planted in the ground, it is false that those acorns are not “oak” until they are planted. The reason the acorn can produce a tree at all is that both are already instances of the same thing, namely “oak.” The young oak grows and eventually turns into an old oak with the help of nourishment from the soil, water from the sky, and sunshine. The soil, sunshine, and water permit it to grow to a more advanced stage of what it intrinsically is.

Similarly, while it is true that embryos don’t become adults unless they are implanted in a uterus, it is incorrect that those embryos are not human beings unless that implantation occurs. When an embryo is not implanted, it is rendered unable to nourish itself, and it gradually starves to death. If a newborn were locked alone in a room where it couldn’t ever reach its mother’s breast for nourishment, it would eventually die of starvation and dehydration. Because the baby never succeeded in attaching to its mother’s breast, this does not imply that it never became a human being. It only implies that it never became an adult human being. Similarly, it would be false to say that an embryo that never attached to its mother’s uterus had failed to become a human being. That embryo was clearly a human being, but one who couldn’t find nourishment, and ended up dying before he or she could reach a later stage like infancy, adolescence, or adulthood. The breast and the uterus are really nourishment-delivery systems for helping little human beings during the early stages of their existence -- tender maternal mechanisms for sheltering and nourishing them as they grow towards more mature stages.

These examples remind us of the regrettable situation we encounter ever more frequently today, a situation where clear thinking becomes the first casualty of agenda-driven positions. As lawmakers, Hollywood figures, and even well-educated intellectuals become convinced that we must harvest embryos for parts, they scramble for arguments that may seem seductive at first, but ultimately lack rigor, substance and truth.

Father Tadeusz Pacholczyk, Ph.D. earned his doctorate in neuroscience from Yale and did post-doctoral work at Harvard. He is a priest of the diocese of Fall River, and serves as the Director of Education at The National Catholic Bioethics Center in Philadelphia.