The link you gave is to the testimony of an "expert" before congress. Whenever you encounter expert evidence, there are three basic questions you need to ask.
- Does this person have the relevant expertise—are they in a position to know what they say they know?
- Is this person biased?
- Is this person's claim backed up by other experts?
Things start to fall apart a bit more when it comes to the issue of bias. Condic doesn't have any direct conflict of interest, like a financial stake in the outcome of this debate. However, googling around makes it clear that she is an activist. She writes for the conservative religious magazines like First Things and The Public Discourse. This makes it very likely that she is going to slant the facts as much as she possibly can in favor of her political view. Now this alone is no reason to discount her testimony. Almost everyone who writes on an issue like this is going to have strong political views of one sort or another. But this is something to bear in mind when considering her testimony
It is on the third question that the testimony here really falls apart. Condic's claim is not backed by what other experts say; it is contradicted by it. This article, by Susan J. Lee and colleagues, looks at all the relevant research. This is what they call in science a "survey article": It doesn't present original research. Instead it looks at all the research currently available to determine if all the evidence collected so far can give us a conclusion on an important issue. In this case, the authors dug through over a thousand articles in their examination of the evidence. Their conclusion: fetal perception of pain is unlikely before the third trimester."
So how does Condic reach a different conclusion than all the other researchers? The answer is illuminating: she is using different standards for what counts as evidence for the perception of pain. Lee et al. define pain as "a subjective sensory and emotional experience that requires the presence of consciousness to permit recognition of a stimulus as unpleasant." In other words, there has to be a brain present to be conscious of the pain, and there is no evidence of enough brain development for consciousness to happen until the third trimester. Condic, on the other hand, is just looking for a reflex reaction in response to stimulus: " The neural circuitry responsible for the most primitive response to pain, the spinal reflex, is in place by 8 weeks of development. This is the earliest point at which the fetus experiences pain in any capacity."
So the difference here is really philosophical. It is about what counts as pain, and what counts as evidence of pain. Condic is counting reflex responses to stimuli as pain. But even a detached cockroach leg can have a reflex response to a stimulus. This is actually an experiment you can do at home, as this video explains. Click here to skip to the part where a detached roach leg twitches in time to a Beastie Boys song. (You might not want to do that, though, if you are grossed out by roaches.)
Furthermore, the circuitry that is present in this detached cockroach leg is all that has developed in the fetus by 8 weeks gestation. The circuit uses serotonin and something called substance P. Its action is inhibited by endorphins. The machinery—or as philosopher Bernard Rollin put it, the "plumbing of pain"—is the same. It just isn't hooked up to anything. All of this can leave us quite confident that a fetus at 8 weeks gestation cannot feel pain.
(A lot of this is actually covered in Taking Animals Seriously: Mental Life and Moral Status, a book by one of your textbook authors, David DeGrazia. His focus is on the issue of pain in animals, though, not in fetuses.)