Facts
Contrary to popular TV shows, courtroom battles are not about competing facts. There are no facts in a trial until the end, when the judge decides what the facts are.
Lawyers don’t introduce facts, they introduce evidence, typically in the form of documents, or drawn from the mouths of witnesses. We call this latter form viva voce. On very rare occasions you get to wave around a gun or a knife, but that is mostly TV stuff.
After all the evidence is in, the judge or the jury then weigh it all up to see what makes most sense to them. After that, some evidence is given the status of fact, while some is rejected. Then the relevant law is applied to the decided facts.
Various rules of evidence are applied to include, exclude, or give varying weights to different forms of evidence. For example, hearsay (second hand evidence) is never given a warm welcome, but sometimes may be allowed in as you might allow a sopping wet dog if circumstances are right.
Most rules of evidence deal with “weight” as well as “admissibility”, so it may be the judge will allow in a certain piece of evidence, but give it scant effect.
Now, these legal rules are fascinating, and helpful if you’re watching a courtroom drama. But they are also highly relevant in everyday life. They are, after all, simply a highly refined form of common sense.
What they tell us is to withhold judgment until we’ve heard the full story, to be skeptical about sketchy sources, and to weigh up all the evidence before coming to conclusions.
In the end, there can only be one set of applicable facts. There are no “alternative facts”, and Kellyanne Conway, legally trained, should be ashamed of herself for trying to say otherwise. Perhaps she was trying to take our eyes off the evidence.
In life, as in law, we need to consider and weigh all the evidence with care before we make “fact-based” decisions.