M Mechanical Philosophy: with the overall rejection of causes in nature other Reductionism and than material and efficient causes. Hence reduc- Foundationalism tionism should be understood as a strategy of explanation rather than necessitating particular Tzuchien Tho ontological commitments. Department of Philosophy, University of Bristol, While reduction to a brute entity or a series of Bristol, UK fundamental elements can be traced back to the pre-Socratics, foundationalism, as we understand Related Topics it, is more exclusively associated with the emer- Mechanical philosophy · Reductionism · gence of modern philosophy. While reductionism Foundationalism · Demonstrative knowledge · is ancient, foundationalism, on the other hand, is Atomism · Experimental philosophy · more exclusively associated with the emergence Rationalism · Empiricism · Scepticism of modern philosophy. Although the term is not an (Skepticism) · Laws of motion actor’s category, thinkers such as Descartes sought to overcome the threat of (self-imposed) hyperbolic skepticism through the establishment Introduction of foundational knowledge. However, earlier theories of knowledge such as what we find in Reductionism, the mode of natural explanation the Aristotelian-scholastic tradition could also be which reduces complex phenomena (including called “foundationalist” in the sense that it sets up mental phenomena) to simple and epistemically a hierarchy for the degrees of knowledge, where or ontological brute entities or sensibles, is not an we move from less certain ways of knowing and exclusively modern trend. All pre-Socratic philos- move “up” to apodictic knowledge ophers are known through their various proposals (demonstrative) which achieves the highest and for a reductionist ontology (i.e., water, indivisi- most certain form. We find in early modern bles, four fundamental elements, etc.). Reduction- foundationalist thinking, borrowing from the ism in modern philosophy is often understood as image of Euclidian demonstration, an inverted the sine qua non of mechanical philosophy. hierarchy that moves from the ground of a small Among the various sects of this general theoreti- number of certain knowledge to more complex cal tendency in the early modern period however, forms. The key difference here is that Aristotelian to what a reductionism would reduce was a matter knowledge works “up” toward certainty where of much debate. Yet some of the common moti- Cartesianism is grounded “down” in certainty. vation among these tendencies can be identified Of course, Descartes and Aristotle share a © Springer Nature Switzerland AG 2020 D. Jalobeanu, C. T. Wolfe (eds.), Encyclopedia of Early Modern Philosophy and the Sciences, https://doi.org/10.1007/978-3-319-20791-9_142-1 2 Mechanical Philosophy: Reductionism and Foundationalism common recognition of geometrical demonstra- to provide conditions beyond mere geometrical tion as apodictic. However, Descartes grounds relationships.) However, for a broad number of knowledge on the clearness and distinctness of key mechanists like Gassendi and Boyle, this ideas, of which geometrical certainty is a paradig- convergence does not follow. For a standard set matic case. Hence complex forms of knowledge of canonical thinkers in the tradition, it is ontolog- are certain if they are rooted in the solid founda- ical reductionism rather than epistemic tion of fundamental axiom-like clear and distinct foundationalism that most characterizes this pro- ideas. Hence, while reductionism was a strategy ject of mechanical philosophy. of explanation, foundationalism was a method of The standard identification of mechanical phi- knowledge. losophy with materialism and atomism This entry will address the unique confluence (understood by some scholars as one and the of reductionism and foundationalism in the same for the pre-modern and early modern period) mechanical philosophy of the early modern is not entirely mistaken. The term “mechanical period. The result of this confluence of a mode philosophy” was first used by H. More and of explanation with a method of knowledge is that R. Boyle (Hattab 2011; Anstey 2000). While only reduction to mechanical principles consti- Boyle did not make any ultimate commitment to tutes well-founded knowledge. However some indivisibles, the project of “mechanical or corpus- thinkers within the tradition also sought to undo cular philosophy” was rooted in the use of atom- the restrictive implications of this confluence istic hypotheses as a means of designating the without rejecting the first fruits of the mechanistic proper domain of natural explanation even when program. the authors were not fully committed to indivisi- bles (Pyle 1995; Boyle 1999, I, 474). (The relation between a hypothetical commitment to atomism The Internal Problems of Reductionist and the legitimacy of mechanical philosophy in Explanation in Mechanical Philosophy Boyle has been litigated between A. Pyle, A. Clericuzio, P. Anstey, and A. Chalmers in a We have indicated above that reductionism and series of corresponding articles. See Anstey 2002; foundationalism are different aspects at work in Chalmers 2002; Clericuzio 1990, 2000; Pyle early modern natural philosophy. In the case of 2002, 2018.) However, if we expand the term Descartes, these are distinct but mutually “mechanical philosophy” to a wider set of figures supporting projects: the reduction of the natural to include the Italian contingent featuring world to its ontological basis in extended sub- Guidobaldo del Monte, Galileo, and the Galilean stance (res extensa) is in deep sympathy with the school, the atomistic doctrine cannot be consid- foundation of knowledge in clear and distinct ered a necessary aspect of the reductionist posi- ideas. Since geometry is a priori and based on tion (Garber 2002). “Mechanics” in this tradition clear and distinct ideas, the reduction of physical prescribes a form of explanation that reduces to reality to instantiated geometrical relations allows the five (or six) classical machines (Guidobaldo for a convenient convergence of reductionism and 1577, cited in Garber 2002). foundationalist epistemology. Though Cartesian Understanding God as the divine artificer of a matter (res extensa) is inert, the laws of material complex machine (the world) was not uncommon interactions and transformation are sustained by for all sects of the mechanical tradition. However, God’s decree, concurrence, and conservation this view does not have to imply anything about (AT VIII, 61; CSM I, 240; Arthur 2007). The the ultimate constituents of reality. (The term official view here is that there is simply nothing “mechanistic philosophy” may now seem a bit other than geometrical truths to be known about nominalistic between those who self-professed the nature of extended beings. (This is compli- and those whom later historians called “mecha- cated by the ambiguous account of the laws of nistic.” We make the distinction while tarrying nature in the Principia Philosophiae which appear with the ambiguity. See Boudri 2002.) Insofar as Mechanical Philosophy: Reductionism and Foundationalism 3 reductionist explanation does not have to commit phenomena outside of spatial ones. While matters to entities at the irreducible level of reality, the like spatial position and locomotion (change in reduction to mechanical aggregates can serve as place) can be geometrically explained through fun- the models for the explanation of phenomena. damental constituents or parts mechanically Nonetheless, this view does incur the ultimate arranged, properties like heat, color, and even theoretical burden of implying that motion must weight (or mass) require further elaboration. This be an extramundane input to nature. Like any was a problem with little straightforward agree- machine, what is arranged is bodies. This does ment among the mechanical philosophers. not imply that the machine is operative through Prominent atomists like Gassendi and Boyle, some internal principle as atomists like Gassendi though differing in their commitment to the view, held or according to the Leibnizian theory of did appeal to features of atoms that should be immanent “living force.” The Aristotelian tradi- understood as qualities or principles independent tion affirmed natural motions and places due to of their indivisibility. Most intuitively, color is causes (final and formal) that mechanists saw as interpreted as a sensory effect of the texture of occult and illegitimate. The actuality of an imma- indivisibles. More problematically, the property nent principle of motion in nature remained a of heat was speculated to be reducible to the debate in this domain well into the eighteenth “calorific” or “frigorific” atoms which may reside century. The use of reductionistic mechanism in in particular bodies (Gassendi 1658, I, 394–401; the life sciences where immanent organic growth Boyle 1999, IV, 380–381). (As ever, Boyle is (the preeminent form of Aristotelian motion) was skeptical of this possibility but seriously main- seemingly irreducible also remained an abiding tains the hypothesis for experimental purposes. difficulty (Des Chene 2001; Hutchins 2015; See Pyle 2018.) The danger here is that this view Baldassarri 2019). Nonetheless Descartes’ affir- reintroduces the Aristotelian appeal to principles mation of reductionism and foundationalism was and essences that the reduction to atoms was consistent on this account. Matter was inert and supposed to avoid. Of course we cannot expect motion only exists through an external