Talk of "alternative facts" has been the occasion for some mockery in the news lately since Trump spokeswoman Kelly Anne Conway used the term to describe press secretary Sean Spicer's interpretation of the attendance figures at President Trump's inauguration. Mr. Spicer's generous estimate of the crowd's size was at considerable variance with other estimates, but he insisted that the audience for the inauguration of Mr. Trump, worldwide, was the largest ever.
When asked about this by NBC's Chuck Todd Ms. Conway declared that Mr. Spicer had access to "alternative facts," a response that Mr. Trump's political foes have been deriding ever since. Mr. Todd sniffed that "alternative facts are not facts" (which is patently false). Others have compared her use of the term to Orwellian "newspeak" or "doublespeak," which is surely a strained comparison. Orwell had in mind the ability to hold two contradictory thoughts in one's mind simultaneously, but there's nothing contradictory about alternative facts.
Evidently, the concept to which Conway was referring is foreign to those who've been making merry at her expense, but their derision simply puts on display their own lack of epistemic sophistication. There's nothing ludicrous or contradictory about the idea of "alternative facts." Indeed, such facts are prominent in any debate over any issue that anyone might think of.
Take for a simple example an argument over the question whether or not abortion should be legal. On one side of the debate are certain facts about the obligation of society to protect the weakest and most helpless among us, the status of the unborn child as a person or potential person, the effect of abortion on the mental health of the mother, etc. All of these facts might lend themselves to the conclusion that abortion should be illegal.
On the other side are a set of alternative facts, facts about the well-being of the mother, the prospects of a child brought into the world unwanted, the right of a woman to control what happens inside her body, etc. All of these facts support the alternative conclusion that abortion should be legal.
The alternative conclusion is supported by alternative facts. The error Ms. Conway's detractors make, presumably, is that they seem to confuse alternative facts with contradictions, but as the above example illustrates, alternatives need not be contradictory. They are simply different facts which lead to a different conclusion. The facts are alternatives in the sense that one could rely on one set of facts or the other and draw different conclusions depending on which set was emphasized.
This is so obvious that it's hard to imagine how anyone who has given the matter just a moment's thought, or who has ever been in a debate, or who has any intellectual integrity, could scoff at Ms. Conway for her use of the term.