A judge’s job is to weigh evidence and make a judgment. The evidence may include the weight of previous opinion, interpretation of the rule book, that is, the Constitution, and the facts of the given case. For example, the issue of whether a woman has the right to control her own biological processes is predominantly one of opinion. Legitimate questions might include:

• Does a fetus have constitutional rights?

• Does a woman have constitutional rights?

Whatever your position, it’s easy to see that matters of interpretation, opinions, are dodgy things. Facts are not. Had the original document remained unamended, the president would have no constitutional rights whatsoever and would count as just 3/5 of a man.

Judgment of the legitimacy of a fact must be predicated on physical evidence. Any other approach is arbitrary and arbitrary legal decisions are anathema to democracy.

The choice of a nominee to the Supreme Court ought to depend strongly on the prospect’s record of interpreting facts and arriving at conclusions.

A judge can’t be expected to exercise expertise in all areas – no more nor less than can a scientist. Like scientists, judges must have faith in expert testimony. They must question it and probe its consistency with other known facts, but since they cannot carry out their own investigations into all things relating to the question at hand they must ultimately bow to evidence in its preponderance as related by experts.
Here is a short test, a litmus quiz if you will, for whether a nominee is capable of using related evidence to determine a question of fact:

• Do you understand that Earth is at least 4.5 billion years old?

• Do you accept that a process of natural selection has governed the evolution of life on this planet?

• Do you realize that carbon dioxide heats faster than air when exposed to sunlight and that the fuel human beings burn is sufficient to increase the concentration of carbon dioxide by more than half a percent each year?