<Dd> "In order to achieve completeness in our knowledge of nature, we must start from two extremes, from experience and from the intellect itself...The former method must conclude with natural laws, which it has abstracted from experience, while the latter must begin with principles, and gradually, as it develops more and more, it becomes ever more detailed . Of course, I speak here about the method as manifested in the process of the human intellect itself, not as found in textbooks, where the laws of nature which have been abstracted from the consequent experiences are placed first because they are required to explain the experiences . When the empiricist in his regression towards general laws of nature meets the metaphysician in his progression, science will reach its perfection ." </Dd> <P> Ørsted's "First Introduction to General Physics" (1811) exemplified the steps of observation, hypothesis, deduction and experiment . In 1805, based on his researches on electromagnetism Ørsted came to believe that electricity is propagated by undulatory action (i.e., fluctuation). By 1820, he felt confident enough in his beliefs that he resolved to demonstrate them in a public lecture, and in fact observed a small magnetic effect from a galvanic circuit (i.e., voltaic circuit), without rehearsal; </P> <P> In 1831 John Herschel (1792--1871) published A Preliminary Discourse on the study of Natural Philosophy, setting out the principles of science . Measuring and comparing observations was to be used to find generalisations in "empirical laws", which described regularities in phenomena, then natural philosophers were to work towards the higher aim of finding a universal "law of nature" which explained the causes and effects producing such regularities . An explanatory hypothesis was to be found by evaluating true causes (Newton's "vera causae") derived from experience, for example evidence of past climate change could be due to changes in the shape of continents, or to changes in Earth's orbit . Possible causes could be inferred by analogy to known causes of similar phenomena . It was essential to evaluate the importance of a hypothesis; "our next step in the verification of an induction must, therefore, consist in extending its application to cases not originally contemplated; in studiously varying the circumstances under which our causes act, with a view to ascertain whether their effect is general; and in pushing the application of our laws to extreme cases ." </P> <P> William Whewell (1794--1866) regarded his History of the Inductive Sciences, from the Earliest to the Present Time (1837) to be an introduction to the Philosophy of the Inductive Sciences (1840) which analyzes the method exemplified in the formation of ideas . Whewell attempts to follow Bacon's plan for discovery of an effectual art of discovery . He named the hypothetico - deductive method (which Encyclopædia Britannica credits to Newton); Whewell also coined the term scientist . Whewell examines ideas and attempts to construct science by uniting ideas to facts . He analyses induction into three steps: </P>

Which scientists contributed ideas that became part of the scientific method