In parts one and two of my series “What Does Science Explain?,” I contrasted the metaphysics of the medieval world with the metaphysics of modern science. The metaphysics of modern science, developed by Kepler, Galileo, Descartes, and Newton, asserted that the only true reality was mathematics and the shape, motion, and solidity of objects, all else being subjective sensations existing solely within the human mind. I pointed out that the new scientific view was valuable in developing excellent predictive models, but that scientists made a mistake in elevating a method into a metaphysics, and that the limitations of the metaphysics of modern science called for a rethinking of the modern scientific worldview. (See The Metaphysical Foundations of Modern Science by Edwin Arthur Burtt.)

Early scientists rejected the medieval worldview that saw human beings as the center and summit of creation, and this rejection was correct with regard to astronomical observations of the position and movement of the earth. But the complete rejection of medieval metaphysics with regard to the role of humanity in the universe led to a strange division between theory and practice in science that endures to this day. The value and prestige of science rests in good part on its technological achievements in improving human life. But technology has a two-sided nature, a destructive side as well as a creative side. Aspects of this destructive side include automatic weaponry, missiles, conventional explosives, nuclear weapons, biological weapons, dangerous methods of climate engineering, perhaps even a threat from artificial intelligence. Even granting the necessity of the tools of violence for deterrence and self-defense, there remains the question of whether this destructive technology is going too far and slipping out of our control. So far the benefits of good technology have outweighed the hazards of destructive technology, but what research guidance is offered to scientists when human beings are removed from their high place in the universe and human values are separated from the “real” world of impersonal objects?

Consider the following question: Why do medical scientists focus their research on the treatment and cure of illness in humans rather than the treatment and cure of illness in cockroaches or lizards? This may seem like a silly question, but there’s no purely objective, scientific reason to prefer one course of research over another; the metaphysics of modern science has already disregarded the medieval view that humans have a privileged status in the universe. One could respond by arguing that human beings have a common self-interest in advancing human health through medical research, and this self-interest is enough. But what is the scientific justification for the pursuit of self-interest, which is not objective anyway? Without a recognition of the superior value of human life, medical science has no research guidance.

Or consider this: right now, astronomers are developing and employing advanced technologies to detect other worlds in the galaxy that may have life. The question of life on other planets has long interested astronomers, but it was impossible with older technologies to adequately search for life. It would be safe to say that the discovery of life on another planet would be a landmark development in science, and the discovery of intelligent life on another planet would be an astonishing development. The first scientist who discovered a world with intelligent life would surely win awards and fame. And yet, we already have intelligent life on earth and the metaphysics of modern science devalues it. In practice, of course, most scientists do value human life; the point is, the metaphysics behind science doesn’t, leaving scientists at a loss for providing an intellectual justification for a research program that protects and advances human life.

A second limitation of modern science’s metaphysics, closely related to the first, is its disregard of certain human sensations in acquiring knowledge. Early scientists promoted the view that only the “primary qualities” of mathematics, shape, size, and motion were real, while the “secondary qualities” of color, taste, smell, and sound existed only in the mind. This distinction between primary and secondary qualities was criticized at the time by philosophers such as George Berkeley, a bishop of the Anglican Church. Berkeley argued that the distinction between primary and secondary qualities was false and that even size, shape, and motion were relative to the perceptions and judgment of observers. Berkeley also opposed Isaac Newton’s theory that space and time were absolute entities, arguing instead that these were ideas rooted in human sensations. But Berkeley was disregarded by scientists, largely because Newton offered predictive models of great value.

Three hundred years later, Isaac Newton’s models retain their great value and are still widely used — but it is worth noting that Berkeley’s metaphysics has actually proved superior in many respects to Newton’s metaphysics.

Consider the nature of mathematics. For many centuries mathematicians believed that mathematical objects were objectively real and certain and that Euclidean geometry was the one true geometry. However, the discovery of non-Euclidean geometries in the nineteenth century shook this assumption, and mathematicians had to reconcile themselves to the fact that it was possible to create multiple geometries of equal validity. There were differences between the geometries in terms of their simplicity and their ability to solve particular problems, but no one geometry was more “real” than the others.

If you think about it, this should not be surprising. The basic objects of geometry — points, lines, and planes — aren’t floating around in space waiting for you to take note of them. They are concepts, creations of the human brain. We may see particular objects that resemble points, lines, and planes, but space itself has no visible content; we have to add content to it.  And we have a choice in what content to use. It is possible to create a geometry in which all lines are straight or all lines are curved; in which some lines are parallel or no lines are parallel;  or in which lines are parallel over a finite distance but eventually meet at some infinitely great distance. It is also possible to create a geometry with axioms that assume no lines, only points; or a geometry that assumes “regions” rather than points. So the notion that mathematics is a “primary quality” that exists within objects independent of human minds is a myth. (For more on the imaginary qualities of mathematics, see my previous posts here and here.)

But aside from the discovery of multiple mathematical systems, what has really killed the artificial distinction between “primary qualities,” allegedly objective, and “secondary qualities,” allegedly subjective, is modern science itself, particularly in the findings of relativity theory and quantum mechanics.

According to relativity theory, there is no single, objectively real size, shape, or motion of objects — these qualities are all relative to an observer in a particular reference frame (say, at the same location on earth, in the same vehicle, or in the same rocket ship). Contrary to some excessive and simplistic views, relativity theory does NOT mean that any and all opinions are equally valid. In fact, all observers within the same reference frame should be seeing the same thing and their measurements should match. But observers in different reference frames may have radically different measurements of the size, shape, and motion of an object, and there is no one single reference frame that is privileged — they are all equally valid.

Consider the question of motion. How fast are you moving right now? Relative to your computer or chair, you are probably still. But the earth is rotating at 1040 miles per hour, so relative to an observer on the moon, you would be moving at that speed — adjusting for the fact that the moon is also orbiting around the earth at 2288 miles per hour. But also note that the earth is orbiting the sun at 66,000 miles per hour, our solar system is orbiting the galaxy at 52,000 miles per hour, and our galaxy is moving at 1,200,000 miles per hour; so from the standpoint of an observer in another galaxy you are moving at a fantastically fast speed in a series of crazy looping motions. Isaac Newton argued that there was an absolute position in space by which your true, objective speed could be measured. But Einstein dismissed that view, and the scientific consensus today is that Einstein was right — the answer to the question of how fast you are moving is relative to the location and speed of the observer.

The relativity of motion was anticipated by the aforementioned George Berkeley as early as the eighteenth century, in his Treatise Concerning the Principles of Human Knowledge (paragraphs 112-16). Berkeley’s work was subsequently read by the physicist Ernest Mach, who subsequently influenced Einstein.

Relativity theory also tells us that there is no absolute size and shape, that these also vary according to the frame of reference of an observer in relation to what is observed. An object moving at very fast speeds relative to an observer will be shortened in length, which also affects its shape. (See the examples here and here.) What is the “real” size and shape of the object? There is none — you have to specify the reference frame in order to get an answer. Professor Richard Wolfson, a physicist at Middlebury College who has a great lecture series on relativity theory, explains what happens at very fast speeds:

An example in which length contraction is important is the Stanford Linear Accelerator, which is 2 miles long as measured on Earth, but only about 3 feet long to the electrons moving down the accelerator at 0.9999995c [nearly the speed of light]. . . . [Is] the length of the Stanford Linear Accelerator ‘really’ 2 miles? No! To claim so is to give special status to one frame of reference, and that is precisely what relativity precludes. (Course Guidebook to Einstein’s Relativity and the Quantum Revolution, Lecture 10.)

In fact, from the perspective of a light particle (a photon), there is infinite length contraction — there is no distance and the entire universe looks like a point!

The final nail in the coffin of the metaphysics of modern science is surely the weird world of quantum physics. According to quantum physics, particles at the subatomic level do not occupy only one position at a particular moment of time but can exist in multiple positions at the same time — only when the subatomic particles are observed do the various possibilities “collapse” into a single outcome. This oddity led to the paradoxical thought experiment known as “Schrodinger’s Cat” (video here). The importance of the “observer effect” to modern physics is so great that some physicists, such as the late physicist John Wheeler, believed that human observation actually plays a role in shaping the very reality of the universe! Stephen Hawking holds a similar view, arguing that our observation “collapses” multiple possibilities into a single history of the universe: “We create history by our observation, rather than history creating us.” (See The Grand Design, pp. 82-83, 139-41.) There are serious disputes among scientists about whether uncertainties at the subatomic level really justify the multiverse theories of Wheeler and Hawking, but that is another story.

Nevertheless, despite the obsolescence of the metaphysical premises of modern science, when scientists talk about the methods of science, they still distinguish between the reality of objects and the unreality of what exists in the mind, and emphasize the importance of being objective at all times. Why is that? Why do scientists still use a metaphysics developed centuries ago by Kepler, Galileo, and Newton? I think this practice persists largely because the growth of knowledge since these early thinkers has led to overspecialization — if one is interested in science, one pursues a degree in chemistry, biology, or physics; if one is interested in metaphysics, one pursues a degree in philosophy. Scientists generally aren’t interested in or can’t understand what philosophers have to say, and philosophers have the same view of scientists. So science carries on with a metaphysics that is hundreds of years old and obsolete.

It’s true that the idea of objectivity was developed in response to the very real problem of the uncertainty of human sense impressions and the fallibility of the conclusions our minds draw in response to those sense impressions. Sometimes we think we see something, but we don’t. People make mistakes, they may see mirages; in extreme cases, they may hallucinate. Or we see the same thing but have different interpretations. Early scientists tried to solve this problem by separating human senses and the human mind from the “real” world of objects. But this view was philosophically dubious to begin with and has been refuted by science itself. So how do we resolve the problem of mistaken and differing perceptions and interpretations?

Well, we supplement our limited senses and minds with the senses and minds of other human beings. We gather together, we learn what others have perceived and concluded, we engage in dialogue and debate, we conduct repeated observations and check our results with the results of others. If we come to an agreement, then we have a tentative conclusion; if we don’t agree, more observation, testing, and dialogue is required to develop a picture that resolves the competing claims. In some cases we may simply end up with an explanation that accounts for why we come up with different conclusions — perhaps we are in different locations, moving at different speeds, or there is something about our sensory apparatus that causes us to sense differently. (There is an extensive literature in science about why people see colors differently due to the nature of the eye and brain.)

Central to the whole process of science is a common effort — but there is also the necessity of subduing one’s ego, acknowledging that not only are there other people smarter than we are, but that the collective efforts of even less-smart people are greater than our own individual efforts. Subduing one’s ego is also required in order to prepare for the necessity of changing one’s mind in response to new evidence and arguments. Ultimately, the search for knowledge is a social and moral enterprise. But we are not going to succeed in that endeavor by positing a reality separate from human beings and composed only of objects. (Next: Part 4)