Groucho Marxism

The theory of relativity comprises two physics theories by Albert Einstein: special relativity and general relativity. These theories transformed theoretical physics and astronomy during the 20th century, superseding a 200-year-old theory of mechanics created primarily by Isaac Newton. Einstein published the theory of special relativity in 1905, building on many theoretical results and empirical findings obtained by Albert A. Michelson, Hendrik Lorentz, Henri Poincaré and others. Einstein then developed general relativity between 1907 and 1915, with contributions by many others after 1915. The term ‘theory of relativity’ was based on the expression ‘relative theory’ used in 1906 by Max Planck, who emphasized how the theory uses the principle of relativity.

The principle of relativity states that the laws of physics are the same for all observers in any inertial reference frame. A reference frame is just a coordinate system, whose origin, orientation, and scale have been specified in physical space. An inertial reference frame is one in which objects exhibit inertia: they remain at rest or in uniform motion relative to the frame until acted upon by external forces. The principle of relativity is the first postulate upon which special relativity is based. The second postulate is that the speed of light in vacuum is the same for all observers, regardless of their relative motion or of the motion of the light source. These postulates lead to many surprising and counterintuitive consequences.

One of these consequences is relativity of simultaneity: two events, simultaneous for one observer, may not be simultaneous for another observer if the observers are in relative motion. Another is time dilation: moving clocks are measured to tick more slowly than an observer’s ‘stationary’ clock. A third is length contraction: objects are measured to be shortened in the direction that they are moving with respect to the observer. A fourth is that there is a finite maximum speed: no physical object, message or field line can travel faster than the speed of light in vacuum. And a fifth is mass–energy equivalence: energy and mass are equivalent and transmutable. The last consequence is summarized by the equation E = mc², perhaps the most famous equation in all of physics.

What is interesting about this is that all of these counterintuitive consequences arose from Einstein making a simple shift in perspective. Instead as seeing objects moving relative to a space which is fixed and absolute, he realized that it only makes sense to think of objects as moving relative to a particular reference frame. Thus, according to Einstein, it makes no sense to say that an object has an absolute velocity; all we can say is that it has a relative velocity. Another way of putting this is that it we can only measure the velocity of one object relative to the velocity of another object. This demonstrates that velocity is a relative rather than an absolute concept. The same goes for other physical quantities such as length and time.

I think we need to apply a similar shift in perspective in the social sciences. Instead of seeing concepts like wealth and happiness as absolute, we should view them as relative. We cannot in general say that someone is ‘wealthy’ or ‘happy’; all we can say is that they are wealthy or happy relative to some reference frame. It makes no sense to measure wealth an happiness using an absolute scale. In fact this is even more true of social concepts like happiness than physical concepts like velocity. Whereas we can say the velocity of one object has some particular quantitative value relative to the velocity of another object, we cannot say that someone’s well-being has a particular quantitative value relative to someone else’s well-being.

Realistically, all we can say is that one person is happier than another person; it makes no sense to say that they are 3 times as happy. The idea that we can measure well-being on a cardinal or absolute scale is a fallacy upon which the entire philosophy of utilitarianism is based (see my previous blog post on this for more details). The truth is that concepts like well-being can only be measured on an ordinal or relative scale. This simple insight has far-reaching consequences for how we should structure society. It makes no sense to try to maximize overall well-being, as it isn’t even possible to quantify this in this first place, even in principle. Instead, our aim must be to minimize the discrepancy in relative well-being between different people. This is the only optimization protocol that makes any sense.