evidence witnesses slander civil-judgment prejudice
Why is a witness evidentiary if it cannot be disproven?
<p>I am having trouble understanding the logic of the law discrepancy between hearsay and witness testimony in towards proving guilt rather than innocence.</p>

<p>The general  rule is that sworn testimony of a witness with personal knowledge of the facts is competent evidence. A guilty verdict in a criminal case will only be upheld on appeal if sufficient competent evidence to support that verdict was admitted at trial.</p>
<p>The hearsay rule is not about the reliability of witness testimony in general, it is about quality control with respect to witness testimony.</p>
<p>The primary effect of the hearsay rule is to prevent someone trying to prove something from doing so by affidavit without making the person who actually made that statement that proves something come into court where they are subject to cross-examination. This shifts the burden of getting someone into court from the person trying to defend against evidence to the person relying upon the evidence.</p>
<p>Cross-examination of a live witness is more effective at resolving subtle ambiguities or omissions in a statement than an unresponsive affidavit or testimony from someone who merely heard someone else say something.</p>
<p>The hearsay rule also minimizes the risk illustrated by the children's game of &quot;telephone&quot; where one person passes a statement to another in many iterations and the person at the end of the line announces the statement, which is often greatly degraded or distorted from the original statement. Hearing something straight form the &quot;horse's mouth&quot; avoids that.</p>
<p>There are many circumstances, however, where these considerations are not paramount, which is why there are myriad exceptions to the hearsay rule.</p>
<p>Witness testimony under oath and subject to cross-examination still does not mean that the party offering it automatically proves what the witness testified to in most cases. The finder of fact can weight the credibility of the witness, physical evidence, documents that are not hearsay or are exempt from the hearsay rule, circumstantial evidence contrary to witness testimony, or of course, directly contrary testimony, in deciding what the real facts of a case are, and indeed, cases rarely go to trial unless there are disputes concerning what the facts of the case really are.</p>

<p>Witness testimony can be disproved, or perhaps the better word would be countered. One side can call a different witness who will tell a contradictory story. Physical evidence which contradicts a witness account can be introduced.  Cross-examination can reveal contradictions in a witness's testimony. It can also cast doubt on a witness's credibility or reliability. Other evidence can show that a witness has a motive to lie or to favor one side of a case. In the case of eyewitness identification in particular, scientific (expert) evidence can show the error rate of such testimony, and the circumstances in which it is likely to be more or less reliable. And closing argument from a lawyer can attack the consistency, probability an likelihood of a witness account.</p>
<p>The trier of fact (Judge or Jury) can take all this into account in determining how much, if any, weight to give the testimony of a particular witness.</p>

<p>Hearsay adds an extra abstraction on witness testimony, which leads to the possibility that, at the same time:</p>
<ul>
<li>The witness' statement is correct</li>
<li>The facts stated by the witness did not actually happen</li>
</ul>
<p>Take the example of Bob. He's currently on trial, he is accused of breaking the flag pole on top of the building.</p>
<p>John testifies. John didn't see Bob, but he was told by Mary that she saw Bob on the roof of the building (let's take it as a fact that Mary did in fact make this statement to John). John makes the following statement:</p>
<blockquote>
<p>&quot;Mary told me Bob was on the roof of the building&quot;</p>
</blockquote>
<p>This statement is factually correct. Mary did tell John that she saw Bob on the building. John is generally expected to be a very believable witness since he is telling the genuine truth.</p>
<p>However, John's statement does not help us in establishing whether or not Bob <em>actually</em> was on the building; because Mary might have been lying to John. Maybe Mary intentionally lied (e.g. to boast about Bob being a daredevil, falsely accuse Bob of improper behavior, ...), or maybe Mary made a genuine mistake (e.g. Mary has bad eyesight and mistook someone else for Bob, ...)</p>
<p>To verify the correctness of Mary's claim, we would need to cross-examine <em>Mary</em>. She's the one making the claim, so she's the one who should be examined.</p>
<p>But we have John in front of us. John cannot help us verify whether Mary was telling the truth or not, because John was the recipient of Mary's statement, not an active participant; so John is &quot;useless&quot; in regards to Mary's claim of seeing Bob on the roof, and therefore Mary's claim should be made (in court) by none other than <em>Mary herself</em>.</p>
<p>This is why we call a claim that the witness has <em>heard but not witnessed</em> to be hearsay. The witness did not witness it. They just heard it said.</p>
