In my previous post, I discussed the nature of metaphysics, a theory of being and existence, in the medieval world. The metaphysics of the medieval period was strongly influenced by the ancient Greeks, particularly Aristotle, who posited four causes or explanations for why things were. In addition, Aristotle argued that existence could be understood as the result of a transition from “potentiality” to “actuality.” With the rise of modern science, argued Edwin Arthur Burtt in The Metaphysical Foundations of Modern Science, the medieval conception of existence changed. Although some of this change was beneficial, argued Burtt, there was also a loss.

The first major change that modern science brought about was the strict separation of human beings, along with human senses and desires, from the “real” universe of impersonal objects joining, separating, and colliding with each other. Rather than seeing human beings as the center or summit of creation, as the medievals did, modern scientists removed the privileged position of human beings and promoted the goal of “objectivity” in their studies, arguing that we needed to dismiss all subjective human sensations and look at objects as they were in themselves. Kepler, Galileo, and Newton made a sharp distinction between the “primary qualities” of objects and “secondary qualities,” arguing that only primary qualities were truly real, and therefore worth studying. What were the “primary qualities?”: quantity/mathematics, motion, shape, and solidity. These qualities existed within objects and were independent of human perception and sensation. The “secondary qualities” were color, taste, smell, and sound; these were subjective because they were derived from human sensations, and therefore did not provide objective facts that could advance knowledge.

The second major change that modern science brought to metaphysics was a dismissal of the medieval world’s rich and multifaceted concept of causation in favor of a focus on “efficient causation” (the impact of one object or event on another). The concept of “final causation,” that is, goal-oriented development, was neglected. In addition, the concept of “formal causation,” that is, the emergence of things out of universal forms, was reduced to mathematics; only mathematical forms expressed in the “laws of nature,” were truly real, according to the new scientific worldview. Thus, all causation was reduced to mathematical “laws of nature” directing the motion and interaction of objects.

The consequences of this new worldview were tremendous in terms of altering humanity’s conception of reality and what it meant to explain reality. According to Burtt, “From now on, it is a settled assumption for modern thought in practically every field, that to explain anything is to reduce it to its elementary parts, whose relations, where temporal in character, are conceived in terms of efficient causality solely.” (Metaphysics of Modern Science, p. 134) And although the early giants of science — Kepler, Galileo, and Newton — believed in God, their conception of God was significantly different from the medieval view. Rather than seeing God as the Supreme Good, the goal or end which continually brought all things from potentiality to actuality, they saw God in terms of the “First Efficient Cause” only. That is, God brought the laws of nature into existence, and then the universe operated like a clock or machine, which might then only occasionally need rewinding or maintenance. But once this conception of God became widespread, it was not long before people questioned whether God was necessary at all to explain the universe.

Inarguably, there were great advantages to the metaphysical views of early scientists. By focusing on mathematical models and efficient causes, while pruning away many of the non-calculable qualities of natural phenomena, scientists were able to develop excellent predictive models. Descartes gave up the study of “final causes” and focused his energies on mathematics because he felt no one could discern God’s purposes, a view adopted widely by subsequent scientists. Both Galileo and Newton put great emphasis on the importance of observation and experimentation in the study of nature, which in many cases put an end to abstract philosophical speculations on natural phenomena that gave no definite conclusions. And Newton gave precise meanings to previously vague terms like “force” and “mass,” meanings that allowed measurement and calculation.

The mistake that these early scientists made, however, was to elevate a method into a metaphysics, by proclaiming that what they studied was the only true reality, with all else existing solely in the human mind. According to Burtt,

[T]he great Newton’s authority was squarely behind that view of the cosmos which saw in man a puny, irrelevant spectator . . . of the vast mathematical system whose regular motions according to mechanical principles constituted the world of nature. . . . The world that people had thought themselves living in — a world rich with colour and sound, redolent with fragrance, filled with gladness, love and beauty, speaking everywhere of purposive harmony and creative ideals — was crowded now into minute corners in the brains of scattered organic beings. The really important world outside was a world hard, cold, colourless, silent, and dead; a world of quantity, a world of mathematically computable motions in mechanical regularity.  (pp. 238-9)

Even at the time this new scientific metaphysics was being developed, it was critiqued on various grounds by philosophers such as Leibniz, Hume, and Berkeley. These philosophers’ critiques had little long-term impact, probably because scientists offered working predictive models and philosophers did not. But today, even as science is promising an eventual “theory of everything,” the limitations of the metaphysics of modern science is causing even some scientists to rethink the whole issue of causation and the role of human sensations in developing knowledge. The necessity for rethinking the modern scientific view of metaphysics will be the subject of my next post.