Rene Descartes, Francis Bacon, Galileo Galilei, and Isaac Newton share a common philosophy. Philosophy operates in a cultural context and these four men would certainly have shared some culture, with each living in Europe, during overlapping time frames, in the aftermath of the Reformation, and with each writing in Latin. Exhaustively comparing their philosophies would reveal areas of distinction and areas of overlap. To show that they share a common philosophy, it suffices to show that the overlap of their respective philosophies is significant. Bowler & Morus (2005, pp. 39-40) contend that the philosophy of what has come to be called the scientific revolution includes (1) an opposition to traditional authority as the basis of knowledge, (2) an embracing of the “language of mathematics” as the language of nature, and (3) the recognition of experience as the standard of truth. Taken together, these are significant. Though the boundaries of the scientific revolution are fuzzy and the participants numerous (Bowler & Morus, 2005, Chapter 2), the contributions of Descartes, Bacon, Galileo, and Newton to early modern science mark them as representative founding figures, expected to embrace these three elements of the revolution’s philosophy. Do they?
It is convenient to begin a comparison of philosophies by viewing their negative space. Revolution is driven by revolutionaries, individuals radically discontent with the established order. Like barnacles on a ship’s hull, revolutionary philosophies are adversarial to the old regime but also unavoidably shaped by it. The political revolutions that produced republics in France, Russia, and Iran; for all their differences, would certainly share “monarchy” in the negative space of their shared revolutionary philosophy. To the scientific revolution’s nascent natural scientists, the Scholasticism of medieval Christianity was the old regime and Aristotle was its king.
It is in this spirit that Bacon (1901, p. 42) accuses Aristotle of philosophical fratricide by “destroying other systems (as the Ottomans do to their brethren).” The editor explains that the early Sultans were reputed to consolidate power through familicide but Bacon’s reference also evokes the fratricides of Romulus (Rome’s founding king), Shakespeare’s Richard III (England’s final Plantagenet king) and Genesis’ Cain (first of humanity’s progeny). Aristotle acts as a kidnapper to true philosophy when “he drags experiment along as a captive” (p. 36) making it “completely subservient” (p. 29) and leaving it “impure and corrupted” (p. 77). Aristotle’s philosophy is “fiction” (p. 191), “little more than useless and disputatious” (p. 29), containing “preconceived fancies” (p.29) and “dogmas” (p. 47) that survives from antiquity only because of its “lighter and less solid nature” (p. 54). Bacon’s Aristotle is distinguished from the Sophists mainly in the fact of his fixed address (p. 47). An unfit philosopher-king, Aristotle is “contentious and thorny” (p.70), his teachings merely “the talk of old men to ignorant youths” (p. 47).
In his effort to dethrone Aristotle, Rene Descartes (1903, p. 111) is more circumspect than Bacon, saying euphemistically that he was “characterized by less candour” and “proposed as true and certain what it is probable he himself never esteemed as such.” So, without calling Aristotle a “liar”, Bacon does seems to say that Aristotle lies. For Bacon, Aristotle’s ideas are disproved by history as “men made no progress in knowledge by their means during the many ages they prosecuted them” (p. 123). Later students who came to follow Aristotle’s ideas, did so “blindly”, “corrupted the sense of his writings, and attributed to him various opinions which he would not recognise as his own” (p. 112). So for Bacon, contemporary Aristotelian philosophy is worse even than the discredited actual philosophy of Aristotle.
Scholasticism was not limited to Aristotle and had become integral to medieval Christianity with the bureaucracy and infrastructure that made up the church’s legacy from the old Roman Empire. Organized Christianity valued orthodoxy (Bowler & Morus, 2005, p. 344) and had a tradition of enforcing it – heretics could be burned. It is no wonder that when Galileo, who had “made a name for himself as a controversialist” (Bowler & Morus, 2005, p. 29) found himself facing charges of heresy, he would have actively “engaged in damage control” (Abbot, 2018). After his “condemnation” for “vehement suspicion of heresy” (Abbot, 2018), Galileo is sentenced to prison and spends the remainder of his life under house arrest (Abbott, 2018). Though not literally martyred, Galileo does become a secular saint of sorts, often seen as a martyr to modernity. Galileo had tried the limits of institutional patience and learned that revolution, even scientific revolution, is a dangerous business and this sense of danger is palpable in Descartes’ careful defensiveness as he writes the opening dedication to his Meditations on First Philosophy
Newton, being the youngest of the four, benefits from the efforts of the other three. He lives furthest from Rome, beyond the Inquisition’s reach. Newton is likely the only actual heretic of the group (Bowler & Morus, 2005, p. 48) who declines to take his holy orders as was expected (Westfall, 1983, p. 69). Even so, he has the least to fear and to Aristotle, Newton makes only a dismissive nod when he says “My design in this book is not to explain the Properties of Light by Hypotheses” (Newton, 1730, p. 1). Beyond that, Newton saves his ink for squabbles with the living, e.g. Leibniz. “The opposite of love is not hate, it’s indifference” (Wiesel, 1986) and the living Leibniz receives only Newton’s hate while the dead Aristotle receives the full measure of his indifference. But Newton does share with Bacon, Descartes, and Galileo a revolutionary spirit, a rejection of Scholasticism and ancient authority, particularly Aristotle.
The scientific revolution’s founding fathers have a shared view of the status and role of mathematics in what comes to be known as the natural sciences. Among their varied vocations, all but Bacon is described as a being a mathematician (Watson, 2021), (Heiden, 2021), (Westfall, 2021), and (Urbach et al, 2021). Though Bacon does not contribute new mathematics to the enterprise, he makes clear his view that “the investigation of nature is best conducted when mathematics are applied to physics” (Bacon, 1901, p. 119).
Galileo makes the role of mathematics more explicit, describing it as the language, not just of investigation, but of the universe.
Philosophy is written in this grand book, the universe, which stands continually open to our gaze. But the book cannot be understood unless one first learns to comprehend the language and read the letters in which it is composed. It is written in the language of mathematics … (Galileo, 1623)
For Galileo, the language of the natural sciences is, quite naturally, the universal language of mathematics.
Descartes (1903, p. 77) “reckoned among the number of the most certain truths those [he] clearly conceived relating to figures, numbers, and other matters that pertain to arithmetic and geometry, and in general to the pure mathematics.” Among Descartes’ contributions is the extension of Galileo’s universal language in the form of his eponymous coordinate system. Cartesian coordinates were prerequisite, necessary, but not sufficient, to understanding and communicating Newton’s mechanics.
But, it is Newton who most exemplifies the mathematical perspective in the philosophy of the natural sciences. Like Shakespeare who, when he found his language insufficient to tell the stories he meant to tell, expanded that language; when Newton found his mathematical language (sans calculus) insufficient to describe the mechanics he meant to describe, he expanded that mathematics.
Bacon, Galileo, Descartes, and Newton share an understanding of the privileged status of mathematics, seeing it as the reliable tool, the natural language, and the right framework with which to structure physics and to understand the natural world. This is a significant philosophical view and a view that they share. While these individuals also share Latin as a common written language, it is the language of mathematics that they also share with the natural world.
The scientific revolution’s founding fathers shared the view that reliable knowledge about the natural world is “based on experience” (Bowler & Morus, 2005, p. 39) and the main source of “experience” in the natural sciences is experiment. These founding figures value experiment. That experiment should form a standard for truth is far from obvious. Three of these founders are described as mathematicians (Watson, 2021), (Heiden, 2021), (Westfall, 2021), and (Urbach et al, 2021) and the standard of truth in mathematics is deductive proof, not experiment.
In the radical skepticism of his Meditations on First Philosophy, Descartes (1901, p. 130) demands evidence of everything, even his own existence, before he will accept it. Evidence of his existence comes in the form of an experimental observation (p. 39), albeit the observation of one’s own thought is a near-degenerate sort of experiment. Likewise, when presented with experimental evidence, through the remembrance of dreams (p. 23), that his senses are not reliable, he promptly distrusts his senses. The mere melting of wax (pp. 36-41) leads him to doubt the nature of external objects. The power of experiment to cast doubt is greater than its ability to create surety. As he justifies through a single experiment his belief that thought is localized in the brain, he asserts that he “could establish this fact by innumerable experiments” (p. 200). This shows that, while it takes only a single observation to create doubt, it might take infinitely many to create absolute certainty. He does note (p. 122) that in the face of practical economic considerations, the scope of actual experimentation must be limited.
In Descartes’ hands, experiment is primarily a creator that builds knowledge up on a foundation of assumed absolute ignorance. Galileo does not share this assumption of ignorance, so in his hands experiment is more noted as a destroyer than creator. It is a commonsense understanding that heavy objects fall faster than light ones, yet when subjected to experiment, this common understanding is destroyed (Bowler & Morus, 2005, p. 42). It is both an obvious truth and matter of faith that a flawed but central Earth is surrounded by perfect heavenly bodies, yet when subjected to experiment (Bowler & Morus, 2005, p. 29) centrality and perfection are destroyed and only the flaws of the Earth remain. For Galileo, this must mean dissonance – what does it mean for faith? For Galileo, this dissonance is resolved through a change in his understanding of the truth, as his philosophy is one for which truth and experiment must agree.
In the Novum Organum, Bacon (1901) likewise demonstrates this view of experiment as the reliable basis for a true knowledge of the natural world. His complaint regards a weakness in the philosophy that underlies the experimental enterprise. First, he wants to improve the structure of experimentation so as to increase its reach. “We must not only search for and procure a greater number of experiments, but also introduce a completely different method, order, and progress of continuing and promoting experience” (p. 80). Second, he wants to improve coherence between experimental observation and conceptual abstraction, whose relationship he sees as disjoint. “Those who have treated of the sciences have been either empirics or dogmatical. The former like ants only heap up and use their store, the latter like spiders spin out their own webs” (p. 76). Bacon’s goal is “the discovery of causes” (p. 46) and this requires a unity of action in the experimental process as experimentation is fundamental to the natural sciences.
This unity of action in research and a coherence between observation and abstraction are exemplified by Newton in his Opticks (Newton, 1730) as he explores the “properties of Light by a mathematical way of reasoning, so the truth of them may be manifested by Experiments” (p. 214). Following the form of the Elements of Euclid (Byrne, 1847), Newton begins by presenting definitions, and then axioms, before moving on to propositions. But where Euclid’s propositions are shown to be true by deductive proof, Newton explicitly titles the proof of his first two propositions as “The Proof by Experiment”. Newton understands the ancients’ standard of truth and chooses to change that standard to be consistent with own philosophy, a philosophy that he shares with Descartes, Galileo, and Bacon.
As in Mathematicks, so in Natural Philosophy, the Investigation of difficult Things by the Method of Analysis, ought ever to precede the Method of Composition. This Analysis consists in making Experiments and Observations, and in drawing general Conclusions from them by Induction, and admitting of no Objections against the Conclusions , but such as are taken from Experiments, or other certain Truths. (Newton, 1730, p. 380)
Isaac Newton, Galileo Galilei, Francis Bacon, and Rene Descartes are exemplifying participants of what is commonly called the scientific revolution. They share a revolutionary spirit that rejects ancient authority and seeks to topple Scholasticism and its figure-head, Aristotle. They share a view of mathematics as the common language of nature and of the natural sciences and they share a view of experiment as a foundation for the recognition of truth. These views are shared, they are novel, they are philosophical, and taken together, they are significant. Thus, these four founders of the natural sciences share a common philosophy.