Reductionist Doubts

According to reductionism, every complex phenomenon can and should be explained in terms of the simplest possible entities and mechanisms. The parts determine the whole. This approach has been an outstanding success in science, but this essay will point out ways in which it could nevertheless be giving us wrong ideas and holding back progress. For example, it may be impossible to understand key features of the universe such as its pervasive arrow of time and remarkably high degree of isotropy and homogeneity unless we study it holistically – as a true whole. A satisfactory interpretation of quantum mechanics is also likely to be profoundly holistic, involving the entire universe. The phenomenon of entanglement already hints at such a possibility. 1 Reductionism’s Strengths and Weaknesses “Nature does not begin with elements as we are obliged to begin with them. It is certainly fortunate that we can, from time to time, turn aside our eyes from the overpowering unity of the All and allow them to rest on individual details. But we should not omit ultimately to complete and correct our views by a thorough consideration of the things which for the time being we left out of account” (Ernst Mach, 1883). To get an idea where reductionism’s strong and weak points lie, let’s go to its source in Newton’s worldview: utterly simple laws that govern the motions of bodies in space and time. The law of inertia is the most basic: a force-free body moves uniformly in a straight line forever. Things are almost as simple if bodies interact. When far apart, they move with near perfect inertial motions, but when closer they can, through forces like gravitation, begin to change each other’s motions. If body A has a greater mass than body B, then A affects B more than B does A. With allowance for the masses, action and reaction are equal. The behaviour of a large system of many bodies, in principle the whole universe, can, according to Newton, be entirely explained by the inherent tendency of each body to move inertially modified merely by the forces exerted by all the other bodies in the universe. Just as reductionism proposes, the whole truly is the sum of its parts. Or is it? The weak spot in Newton’s scheme is the very thing that makes it reductionist. The position and motion of individual bodies such as atoms, the simple entities, are defined relative to invisible space and time, the framework in which simple laws can be formulated. Mach [1] and others argued that in reality the position of any one object is defined relative to every other object in the