of lead, there are. One can do the same thing with potassium and argon. Doing some simple math lets one then figure out how old that rock is.
Because the whole solar system is thought to have formed at the same time, we can also look at the ages of meteorites and of rocks astronauts brought back from the moon to get a pretty complete picture of Earth’s history, and its age consistently comes up to be about 4.54 billion years old. This isn’t something we believe, it’s something we measure, like the distance between Minneapolis and Dallas. Claiming that Earth is just six thousand years old is mathematically akin to saying, “No, the distance between Minneapolis and Dallas is not around 942 miles. It’s about six and a half feet.”
An Old Book or Your Own Eyes
The measurements we’ve learned how to do using science sometimes conflict with translations of ancient statements in the Bible that, if taken literally, date Earth’s age at around six thousand years. These statements were made before we knew how to measure such things as the age of rocks, or what an atom was, much less how to count them with a mass spectrometer. A reasonable person would note this and ask: Is it better to base our knowledge on reading an old book, or on observations of nature before our very eyes? It’s a question as old as the scientific revolution. Galileo ran into it often after he began lecturing about what he has seen through his telescope. In 1610, he wrote his friend, the German mathematician Johannes Kepler, “My dear Kepler, what would you say of the learned here, who, replete with the pertinacity of the asp, have steadfastly refused to cast a glance through the telescope? What shall we make of this? Shall we laugh, or shall we cry?”
In 1632, in his book Dialogue Considering the Two Chief World Systems, Galileo recounted a tale to a learned man, a natural philosopher, visiting the home of a Venetian doctor who invited a group in to watch and learn as he dissected a human cadaver. The anatomist knew the philosopher believed, as he had read in an old book, that the nerves originated in the heart. Here’s how Galileo told the story:
The anatomist showed that the great trunk of nerves, leaving the brain and passing through the nape, extended on down the spine and then branched out through the whole body, and that only a single strand as fine as a thread arrived at the heart. Turning to a gentleman whom he knew to be a Peripatetic philosopher, and on whose account he had been exhibiting and demonstrating everything with unusual care, he asked this man whether he was at last satisfied and convinced that the nerves originated in the brain and not in the heart. The philosopher, after considering for a while, answered: “You have made me see this matter so plainly and palpably that if Aristotle’s text were not contrary to it, stating clearly that the nerves originate in the heart, I should be forced to admit it to be true.
If we choose the careful, repeatable science of observation and measurement tied back to nature over the estimates more roughly crafted from the creation stories in the Bible or other old and translated texts, must we reject the rest of religion? Or does it still have value in leading a moral life? But then others ask: Is religion even required for morality? If it is inaccurate, can we take any of it seriously? One can see how easily new knowledge can throw world-views into conflict.
When Does Life Begin?
Another example of the thorny intersection of science with traditional ideas, law, and politics comes from the biosciences. Careful, reproducible observations and measurements have forced us to repeatedly refine our ideas about what life is and when it begins. Is a human being first a life when it emerges from the birth canal? Does it have any legal rights as a person before then? Or is it a life when it is able to survive independently outside of the womb even if it is removed early, as can happen naturally with premature birth or with a Caesarean section? Or is it perhaps a life at quickening (the moment a mother first feels a fetus move, at about four months), as was the legal standard for a life when America was formed? But wait! Perhaps it is really a life when a fertilized egg first implants in the uterine lining, which, based on observations, is the medical definition of when a pregnancy begins. A woman cannot be said to be pregnant until her body begins the chemical and biological changes that accompany a symbiotic hosting of the embryo, can she? If it does not implant, the egg, even if fertilized, is simply flushed. Here we get into a tricky area, because many religious conservatives say, “No, it is a life when egg and sperm meet,” whether or not the fertilized egg ever implants.
But then, a scientist would ask the fundamentalist, is it still a life at the moment of fertilization, even if we know from careful observation that one-third to one-half of fertilized eggs never implant, and as many as three-quarters fail to lead to an ongoing pregnancy? And, of course, that brings up more questions: What are fertilized eggs that never implant? How should we define them, if life occurs at fertilization? As miscarriages? Abortions? Nonpregnancies? Suicides? Murders? Something else? What implications might that definition have—legally, ethically, morally—for the use of birth-control pills that inhibit implantation? Is that abortion, murder, or pregnancy prevention?
As our careful observations of life continue, so does our power both to assist and prevent pregnancy. But as our skills improve, new, more troubling questions form. What if we remove the uterus from the process entirely? Is it a life when sperm and egg are joined in a test tube at a fertility clinic and allowed to divide into a group of, say, sixteen cells that are then frozen for future implantation in a woman desperate to have children? Can the woman be said to be “pregnant” as long as this microscopic clump of frozen cells exists? What does Burwell v. Hobby Lobby Stores say about that? What, if any, rights should these frozen cells possess? And is a child conceived in this way—a “test-tube baby,” as we once called them—without a soul, as was suggested by some religious conservatives in the 1970s? Once born, are the joy they bring and the contributions they make less valuable? If we make a special exception for them, by agreeing that in vitro fertilization is not interfering with God’s plan, or by acknowledging that they do appear to have souls, why? On what basis? And what does that make the dozens of frozen cells we discard after a successful pregnancy?
While we’re pondering these linguistic, legal, and ethical quandaries, our observations lead us to yet another new understanding. We don’t need sperm to fertilize an egg; we can do it with the nucleus of another cell from the same being. We try this, and sure enough, we find we can create many identical genetic copies of a sheep or mouse. We call them clones. But then we have to ask: Is it a life if it is just an ovum that has had its nucleus removed and replaced by the nucleus of another cell, and has then been chemically or electrically shocked to induce the natural process of cell division, without fertilization by sperm? If egg and sperm have never met, is it a life? Or is that creature—possibly, one day, a human—damned or soulless as it was once argued “test tube babies” would be?
Observations tell us that beings produced in nontraditional ways seem to be the same as any other creatures. We have to ask, then, is every one of the roughly 1.5 million eggs a woman has in her ovaries at birth a life with rights? When, exactly, does life begin? Is it true, as the comedy troupe Monty Python sang in The Meaning of Life, that “every sperm is sacred”?
What happens if we transform adult skin cells into stem cells, and those into sperm and egg, and then fertilize one with the other? Is that a clone or something else? What if we take the troublesome term “fertilization” out of the picture? Is it a life if we design its genome on a computer (as scientists at the J. Craig Venter Institute have done), buy a high-quality DNA synthesizer on eBay for $8,000 or so, use it to make fragments of the genome we designed, chemically stitch the fragments together, inject the complete genome into a cell with an empty nucleus, and shock it into replicating? Here, we have made a living, reproducing thing starting with a computer design and a few common chemicals. What does that mean for our ideas about life and our definition about conception? Is it wrong to be doing this? To be asking these questions? Applying these observations? Gaining these powers?
What is life? Is life an unbroken chain of genetic code, running down through the generations, endlessly recombining in new forms? Is it software? Does the software beget the hardware? When does it become an individual with rights? Where do we draw the legal line? The moral line? Can we draw a line at all? Is that the right way to be thinking about it? And if we do, how do we define the terms conception, fertilization, implantation, and pregnancy?