The use of animals in scientific experimentation, or, to use the modern term, vivisection, is far from a modern phenomenon. With the rise of modern empirical experimental methodology in the early modern era, it became increasingly common and by the seventeenth century was consistently practiced by anatomists with varying medical, anatomical, and zoological interests. Anita Guerrini's recent detailed history of animal experimentation in seventeenth-century France mirrors a scientific praxis common, to various degrees, in several European countries at the time. In what follows, however, the scientific aspects of animal experimentation will not interest us in themselves, and we will concentrate only on the ethical dilemmas which this posed for at least some early modern scientists. At a time when such experimentation was done without the use of effective anesthetics, the suffering caused to animals was considerable and, for those conducting the experiments, quite conspicuous. The fact that some of the scientists struggled with the moral complications this entailed offers a good vantage-point from which to begin discussing the consideration of animals in pre-Enlightenment Europe.

Animal experimentation, which had become relatively uncommon in the Middle Ages compared with the experiments conducted in antiquity, was conducted in the Renaissance on an increasingly wide scale. The Catholic Church treated the matter in a manner similar to stoic philosophy, supporting the claim that animals, due to their difference from human beings, were devoid of the right to protection from being experimented upon. One of the most prominent Renaissance scientists who performed vivisections in sixteenth-century Italy was Andreas Vesalius. He was one of the first early modern scientists who recognized the suffering that vivisection caused to animals, yet he accorded it no particular significance, writing that there was very little to learn from vivisection of the brain, since “whether we like it or not, but merely out of consideration for our native theologians, we must deprive brute creatures of reason and thought, although their structure is the same as that of man.” And he continued to note that had he not been at personal risk from religious authorities, he indeed would have performed such experiments on animal brains.