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|Historical Context=In the 17th century, the “method of hypothesis” (i.e. the hypothetico-deductive method) was popular, but it “fell into disfavor by the 1720s and 1730s”. It 1730s it had lost its influence and was replaced by the “gradual accumulation of general laws by slow and cautious , careful inductive methods”, methods influenced by the success of Newton’s Principia. This view was still largely in effect when John Herschel was born in 1792 into a preeminent English scientific family, his father William being a prominent astronomer who is credited with discovering Uranus. He became one of the most respected scientists of his time, and in 1830s England, “one answer to the question of how to be scientific might be, ‘Be as much like Herschel as possible.’” He excelled in pure mathematics, optics (he was a pioneer in the technology leading to photography), astronomy and botany (among others). The inductive method of the day remains apparent in influencing Herschel’s work, but he deviates from it in notable ways. Herschel was , resulting in him being part of the movement which revived the method of hypothesis, . This revival was influenced partly by scientific theories developed in the mid-late 18th century like the wave theory of light, the theory of phlogiston, and Franklin’s fluid theory of electricity , each of which “hypothesized unobservable entities in order hypothesized unobservables to explain observable processesphenomena.” In other words, these hypotheses decidedly did not come from the aforementioned slow and cautious inductive methods. Given the apparent success of at least the wave theory of light, they had to be given some consideration as good, accurate scientific theories. And this is where the method of hypothesis, aided by Herschel and his contemporaries/immediate predecessors (such as Whewell, LeSage, Senebier, and Stewart), came back to become the dominant scientific method.|Major Contributions=John Herschel was born in a preeminent English scientific family, his father William being a prominent astronomer who is credited with discovering Uranus. John became one of the most respected scientists of his time, and in 1830s England, “one answer to the question of how to be scientific might be, ‘Be as much like Herschel as possible.’” He excelled in pure mathematics, optics (he was a pioneer in the technology leading to photography), astronomy and botany (among others). In 1831, he wrote his Herschel published Preliminary Discourse on the Study of Natural Philosophy (PD), his most prominent work in a brief foray into the philosophy of science. Due to his breadth of study, his contribution to this field was mostly limited to his PD, a compact description of his views on the goal of science, theory construction and theory appraisal. Some authors have also compared the methods outlined therein to Herschel’s actual conduct in his scientific endeavors to ascertain his true beliefs on the scientific method as opposed to the idealized version presented in PD. The sections of PD most relevant to scientific change are parts II and III in which Herschel shares his views on the general concept of a “cause”, on the origin of hypotheses and theories (between which he rarely distinguishes), and on the importance of the deductive appraisal of these theories. ===== On Causes and the Goal of Science ===== Herschel’s idea of the goal of science is to identify the causes behind the phenomena under investigation - not unlike many of his predecessors. Indeed, Herschel’s philosophy of science as portrayed in PD appears at first to be straightforward Humean empiricism. Upon closer examination, however, some ambiguities and subtleties appear. For one, the meaning of the word “cause” in the above-stated goal is unclear - Ducasse identified four possible meanings, but the most accessible and important are the concepts of a “proximate” versus an “ultimate” cause. An ultimate cause is one which, when arrived at, cannot be improved upon in terms of explanatory power, and truly describes the source of the phenomenon in question. A proximate cause can be improved upon, and only practically describes the phenomenon. Herschel’s goal is to identify the ultimate causes, the “ultimate and inward processes of nature”. It is unclear, however, whether Herschel believes we can achieve this goal. In parts of PD, he states that “increasing knowledge only shows us the infinite complexity which both destroys and earthly hope of understanding the totality of the system and simultaneously assures us that the progress of our knowledge can continue forever”, and that we must “limit our view to that of laws, and to the analysis of complex phenomena by which they are resolved into simpler ones, which, appearing to us incapable of further analysis, we must consent to regard as causes.” But in other parts, he suggests that we may somehow be able to approach these ultimate causes, saying that sometimes, in the face of overwhelming evidence in support of a hypothesis, “we are compelled to admit one of two things: either that it is an actual statement of what really passes in nature, or that the reality, whatever it be, must run so close a parallel with it, as to admit of some mode of expression common to both”. So Herschel believes in ultimate causes, and is pessimistic about our capability to reach them - but he thinks that they can be approached and that we are able to tell when we are getting closer. Thus, Herschel’s methodology of science becomes clear - a scientist is to strive for the ultimate cause of a phenomenon, regardless of whether it is possible or not, and this will guide them on the proper path towards an explanation. It is crucial that Herschel believes that sometimes we can say we are approaching or close to ultimate truth, because otherwise this formulation of the aim of science would not be instructive at all. As for how best to do this, we must examine Herschel’s views on theory construction and evaluation.