united-states evidence
To what extent is a &quot;reasonable inference&quot; acceptable as &quot;proof&quot; in a court of law?
<p>In his autobiography, T. Boone Pickens relates the story of how he managed to do a deal with a man on his sickbed. He took the contract to the man's house, was shown to the man's room, and handed the papers and a pen to the man.</p>

<p>The man pulled the covers over the paper, pen, and his head, and the papers were signed.</p>

<p>Pickens' lawyer asked him, "Did you actually see him sign the papers?"</p>

<p>Pickens said something like, "No. But I can swear out an affidavit that I handed the papers to him unsigned, and received them back from him signed."</p>

<p>In this case, there is an inference that it was the man, and not a supernatural being that signed the papers. How acceptable are such inferences in a court of law?</p>

<p>The standard of proof is "on the balance of probabilities", or, "preponderance of evidence", meaning that your claim must be more probable than the other guy's claim. <a href="https://www.law.cornell.edu/rules/fre" rel="nofollow noreferrer">Rules of evidence</a> may preclude using certain kinds of evidence such as rule 403</p>

<blockquote>
  <p>The court may exclude relevant evidence if its probative value is
  substantially outweighed by a danger of one or more of the following:
  unfair prejudice, confusing the issues, misleading the jury, undue
  delay, wasting time, or needlessly presenting cumulative evidence</p>
</blockquote>

<p>A supernatural alternative can, in fact, defeat all forms of evidence, including forensics and "I saw it directly" testimony. The courts do not exclude evidence (all evidence) on the grounds that you can imagine a sci-fi scenario where "it didn't really happen". The rules of evidence more or less encode the cases where evidence is generally found to <em>not</em> be reliable.</p>
