Scientific Truth Matters

As an addition to the previous post, it could be said that the truer your theory is, the more accurate and consistent are your predictions.

Think of the differences between Einstein's theory of general relativity and Newton's universal theory of gravity.

The former is considered to be a more accurate theory of our solar system and universe than the latter. This is because it takes gravity to be basically the curvature of space-time as causally shaped by massive objects like the Sun, rather than as some universal 'force' acting between objects of mass, say, between the Sun and planets. It is because of the curvature of space-time that the planets of our solar system orbit around the Sun rather than due to some sort of 'gravitational force'. As the Nobel Laureate in Physics Ted Wheeler says: massive objects (like the Sun) shape the curvature of the space-time fabric of the universe (the causal origin of gravity), while the space-time curvature of the fabric of the universe (gravity) determines the actual motions of planets around massive objects like the Sun.

The basis for the acceptance of Einstein's theory over Newton's was provided by (as is well known) Arthur Eddington's confirmation of it in 1919 when he confirmed one of the theory's central predictions - the bending of light from a hidden distant star around the Sun. This work of Eddington's established that light from a hidden distant star could only bend around the Sun if in fact the 'fabric' of space-time curved around the Sun itself; which in turn meant that the curvature of space-time (gravity) is causally shaped by a massive object, like the Sun.

Now, in light of this confirmation of Einstein's theory, Newton's is now considered to be a 'false' theory about our solar system and universe. At best, it's only approximately true, up to a point. This subsequently means that it's unable to fully explain and/or make precise predictions about everything. (This is not to say, though, it's a totally useless theory, as illustrated by the way NASA scientists used it in their calculations for sending astronauts to the moon.)

However, on the basis of Einstein's more accurate theory, it is possible to not only causally explain, for instance, changes in the precession of the planet Mercury (something which Newton's theory couldn't do) but also make very accurate predictions about, for example, changes in the precession of planets like Mercury (something which Newton's theory again couldn't do). Indeed, it's proven to be, even up to the very present, a highly successful theory on both an explanatory and predictive front, as demonstrated by its constant empirical confirmation - such as light being observed coming from behind black holes in 2021.

So, what this comparison between Einstein's and Newton's theories shows is that the soundness or the truthfulness of one's scientific theory matters, not only with respect to its causally explanatory powers but also with regards to (especially) its predictive accuracy.

This is, therefore, the lesson that defenders of modern orthodox neoclassical economics should take heed of. It's not enough to just think that economics need not worry about the soundness and/or truthfulness of its economic theories. A false economic theory can certainly give rise to false or inaccurate predictions, despite what a Milton Friedman might think. So scientific truth matters if your aim is to derive consistently accurate predictions about things, whether that be in the natural sciences like physics or in the social sciences like economics.