How much do we take "on faith" in our everyday lives? This question arose in my mind yesterday as I sat through a colleague's talk in my research group's meeting. He was talking about a phenomenon which has been named "optical bullets," and I began to wonder why these are scientifically interesting. The talk in question is to be delivered at the upcoming meeting for the American Physics Society's Division of Plasma Physics. Though I wondered about the importance of optical bullets, I next came to realize that they must be interesting if for no other reason than that Professor Downer was interested in them. In other words, I can place trust in their importance, because a prominent member of the scientific community is also interested in them.

It is certainly true that I could go and verify the importance of optical bullets for myself. I am, after all, and expert-in-training in this field. I very likely will do so, though this is the first time I've heard of these optical bullets, and so I haven't really had the chance to think them over just yet, because another thought immediately followed after all of this musing. Put simply, I realized that although I could go and verify the importance of optical bullets for myself, there are plenty of people who cannot, and ever more people who won't.

My colleague will give his talk, and will submit a paper for peer-review. The reviewers will likely sign off on the paper--which gives optical bullets their legitimacy--and then the paper will be published. Case closed, there are optical bullets. A small handful of people will read this paper with interest, and perhaps conduct research which uses optical bullets, and perhaps the discovery will be a major advance within the field. It is entirely possible that they will be a centerpiece many future advancements in the field of laser-driven plasma wakefield accelerators. It is also entirely possible that they will be forgotten until the next paper published by my colleagues on the topic, and never verified. What will more than likely come to pass, however, is this: their existence will never again be doubted, and people--especially those in the scientific community, will take them for granted without further proof and indeed without even looking at the evidence published in the initial (or subsequent) papers.

Sure, the physics community in general, and the plasma physics community in particular can verify the evidence for themselves--though most will have to take my colleagues "testimony" that his data is real at face value. After all, very few people have any means of actually attempting to verify this data first-hand: his experiment requires the use of very precise conditions, and a very expensive (and powerful) laser system. The physics community at large must take my colleague's word at face value that when he says that his data proves that there are optical bullets, then there must be optical bullets. Well, they at least must accept that his data is reliable, and can then arrive at the conclusion of optical bullets for themselves. A handful of others can perhaps replicate the data on their own laser systems, but for anyone who does not have direct access to the proper lasers systems, sensors, gas guns, etc (literally millions of dollars' worth of equipment) will have to trust in the results produced by these small band of experts.

What about people in the larger scientific community? There are few biologists who could interpret this set of data even if they accepted its veracity. Sure, they could go study physics for several years to verify the calculations part, but none ever will. Even most members of the broad community of physicists would need specialized training in plasma physics to understand the result, and this is with a solid physics background already in place. All of these people will by-and-large have to trust in the honesty and integrity of the people who collected the data first, and in the authority of those who interpret the data second. Moreover, these people would trust in the results, even if they were considerably more "fantastic" than optical bullets. Even my colleague had the need to trust his instruments when collecting the data.

Finally, there are the lay people, that is, the people who are outside the scientific community entirely. These people are told that they must believe whatever the latest scientific theory holds (nevermind that a great many of these theories has been discarded as wrong by the scientific community). They ask for evidence, and are shown the data about which they can make no sense, and then shown the theories, most of which are utterly incomprehensible to them. These lay persons are told by the experts that they just have to trust that the experts know what they're talking about. They are to place faith in the experts' testimony. If the expert sees an optical bullet or finds the Higg's Boson, then it's there.

This is in large part how scientific research is able to progress. A new discovery is made, it is verified by a handful of collaborators or competitors. The next generation of scientists then accepts the discovery with some small amount of evidence (and rarely any first-hand "hard" evidence); by-and-large, the scientific community accepts this new discovery unless or until and overwhelming amount of evidence accumulates against it. And, of course, the vast majority of the scientific community at-large trusts without verification the testimony of the originally discoverers and their collaborators. Science would be unable to progress if every scientist had to verify for himself, both with theory and experiment, every finding and discovery which preceded his work and which made his work possible. Every scientist must state, with Newton, that if he has "seen further it is by standing on the shoulders of giants."

That is the lot of the scientist, to trust the testimony of his peers and predecessors. For the layperson, it is to trust the scientists and their assurances and testimonies. They can question, though only from ignorance, and are ultimately told to merely have faith in the scientific testimony of a few men. They never see the evidence first hand, and would not understand it if they did; still, they are expected to believe. Many see that such courtesy is rarely extended to them when the roles are reversed, and so remain skeptical.