Matter and vacuum in Robert Boyle's natural philosophy

This dissertation examines the concept of vacuum in seventeenth-century natural philosophy and in particular, looks at how Robert Boyle dealt with the issues surrounding the concept of vacuum in his theory of matter. Traditional studies of seventeenth-century natural philosophy agreed that a series of experiments with the mercury barometer and later with Boyle's air-pump unequivocally established the existence of the void, thus refuting Aristotle's contention that nature abhors a vacuum. Recent scholarship has shown that the issues were far more complex than this positivist account reveals.;I studied a dispute between Boyle and Henry More, a prominent Cambridge Platonist, over the proper interpretation of Boyle's early pneumatical experiments and demonstrate firstly, that arguments about the existence of the void were not settled on experimental and empirical grounds alone, but involved more general theological and philosophical considerations. Secondly, I show that Boyle was able to get around traditional objections to the void (the absurdity of claiming the existence of nothing) by reconceptualizing the problem and thereby allowing natural philosophers to incorporate a notion of void into scientific reasoning while keeping it theologically benign.;Boyle used a concept of void heuristically in his scientific reasoning, while at the same time not according it any ontological status. He accomplished this shift by suggesting that vacuum could be conceptualized in concrete terms as the privation of a characteristic in a subject with a natural disposition for that characteristic. In this way vacuities in the world were analogous to blindness in a person. Boyle avoided the persistent philosophical problems surrounding the concept void by referring to it as the absence of matter rather than the presence of a new entity.;Rather than considering this reconceptualization as Boyle's original innovation, marking a dynamic break with traditional thinking, I found evidence that the Renaissance author, Johann Alsted, had also presented the concept of void-as-privation. This lends weight to my claim that innovative concepts in seventeenth-century natural philosophy, developed as part of the successful challenge to traditional Aristotelianism, reflected ideas already formulated by Renaissance thinkers.