&gt; The switch to metric has already taken place in science and engineering (where it&#x27;s most harmful to have 2 systems), largely because of the horror stories from decades past mentioned in the article.<p>A nontrivial fraction of science and engineering is still done using an unholy mix of US customary and metric units. For example: laser optics frequently have diameters specified in inches and focal lengths in millimeters. Even for science experiments, things like screws and threads are SAE&#x2F;UTS and not metric. Parts for machining are often specified in US customary units. Torque requirements are often specified in foot pounds.<p>Non-metric units aren&#x27;t dead in science, but I sure wish they were.