In the history class I'm presently taking we recently finished a book about the Salem witch trials entitled In the Devil's Snare. Several of the history folk in class didn't buy the author's thesis, nor did they enjoy her attempt to write in narrative rather than analytic form. Whether this disdain was due more to the author's skill or to the personal preferences of the others is a question I'll leave you to decide for yourself. In other words, you should pick the book up if you have any interest in Salem. If you don't, the read is still quite instructive on another level of interest, that of human nature and our relationship to the immaterial.
In our modern world most of us have a difficult time reconciling the immaterial or spiritual world with our own. So steeped are we in empirical science and agnostic secularism that we find intolerable or unimaginable the presence of "other-worldly" influence in our every day lives.
Of course, one significant reason for this apprehension could be considered more broadly legitimate. Human beings have a responsibility to uphold the law and protect each other from harms that come out of our depraved nature. The government is given the authority to wield the sword and it is also given the responsibility for upholding justice. But the difficulty is that human beings only have their reasoning powers and a limited amount of knowledge with which to judge any given circumstances. Doesn't the imposition of immaterial considerations make it impossible for us to judge the material actions and circumstances that occur?
I would argue that the situation is much more dire than this question admits. In fact, without a fixed standard for knowledge, a theory of epistemology that does not change, we cannot even be sure that the material world which we evaluate and judge is really something we know at all. Though the immaterial world is not visible and though we have no methods or tools by which we can measure its presence or influence, does it automatically follow that it does not exist or has no, or less influence upon the material world? Affirmative answers to this question have already presupposed the absence of immaterial influence, though no empiricism can prove it so. They say it cannot be falsified and is therefore irrelevant: it is like trying to prove that unicorns exist or do not exist. But what they fail to recognize is that they cannot prove that their empirical methods arrive at true statements about the world, that is, statements that cannot be falsified. The best science is still a guess from a limited amount of examples using estimates of measurement. The fact that their work is thorough, the fact that useful information and practices come out of their work, and the fact that so many people accept these probabilities as true does not negate the fact that history shows that science changes its mind about every fifty to one hundred years since Copernicus, Newton, Einstein and so on into the future.
Science cannot answer satisfactorily any questions about the immaterial world. This is not to say that scientific methods do not provide useful, indeed very useful, information and practices for the benefit of human society and nature at large. However, science does not have any claims that can be validated with certainty, nor does it take a serious interest in anything that is not measurable by natural instruments or means. One cannot measure, for example, the extent to which the Holy Spirit works to heal our bodies when we pray and ask for healing. Unbelieving scientists that dismiss such questions as absurd or unfalsifiable reveal their presuppositions that refuse to account for the immaterial. But science is still full of unexplainable mysteries, and the paradigms by which science advances its conclusions are subject to radical change, moment to moment. In short, most of science is the creation of the human intellect developed from the partial conclusions of inductive experimentation. Useful, but not certain, and certainly not certain to the extent that modern scientists and most Americans seem to espouse.
Still, Christianity, with its robust theories of the spiritual world and the interaction of angels, demons, Satan, and the Holy Spirit presents us with a history of strange and bazaar conclusions as well as methods of understanding. Salem's mixed population of Puritans and others in the midst of a frontier that faced them with famine and disease, friendly and hostile native americans, internal divisions, and strange occurrences had its own strange methods and conclusions for what went on in late 17th century New England. Those Christian rationalists, with whom I might be lumped, have difficulty unpacking the events of Salem, and especially the reasons why learned and unlearned alike found veracity in the claims of such young girls's claims of victimage.
But one can see where deviation from Scripture, its principles, and those conclusions which can be reasonably deduced; combined with the emotions of fear, anxiety, and so on can lead even the most rational of men and women into error. When the most trying circumstances come, we are still best served to cast all of our thought and will upon the Truth of Scripture, pleading with God's Spirit for illumination as to what we are to think and do. There is no other foundation of knowledge that is certain, and no other word that is more meet for faith and living.