Perhaps you have heard it said that relevance is the first principle of the law of evidence.
A. What does this high-sounding principle mean?
1. Does it mean that irrelevant evidence is inadmissible?
2. If so, why is irrelevant background evidence -- background evidence that neither decreases or increases the probability of a fact in issue --, why is such evidence admissible?
3. And how often can it safely be said that evidence is irrelevant?
B. You may have heard it said that (i) there is a difference between relevance and weight and (ii) the weight of evidence is a question for the jury rather than the (trial) judge.
1. If the trial judge does not have the authority to weigh the probative force of evidence, how is the trial judge to determine whether an alleged risk connected with relevant evidence substantially outweighs the probative value of the allegedly prejudicial but relevant evidence?
2. If the trial judge does not have the authority to weigh evidence, how can the trial judge determine whether or not the factual conditions for the application of a privilege have been satisfied?
3. If the trial judge cannot weigh evidence, how can the trial judge determine that the evidence in a case is insufficient to support a verdict?
C. You may have heard it said that when a trial judge assesses the relevance of proffered evidence, the trial judge must assess the chain of inferences upon which the relevance of the proffered evidence depends.
1. Is the judge to assess the net force of such a chain of inferences? If so, must the trial judge assess the probative force of the proffered evidence in such circumstances in order to determine the relevance of the proffered evidence in such circumstances? But isn't it supposedly the job of the jury to weigh evidence?
1A. Don't both the relevance and the weight of evidence always depend on a multitude of ancillary inferences and assumptions and judgments?
2. If neither the offeror nor the trial judge can articulate the inferences upon which the relevance of proffered evidence depends, does it follow that the proffered evidence must be considered irrelevant? Are some sound evidentiary judgments beyond analysis or explanation?
D. You may have heard it said that proof of facts in trials is a matter of probabilities and you may have heard it said that probability determines whether or not evidence is relevant.
1. Does it follow that only probability theory can describe how factual proof works?
2. Does it follow that the law should be honest with jurors and tell jurors precisely what probabilities are necessary for various kinds of verdicts in various kinds of cases or situations?
3. Is it the case that sometimes we speak most imprecisely when we (attempt to) speak with precise numbers?
4. Are numbers (necessarily) dehumanizing? Mechanical? Inappropriately objective? Is their use emblematic of scientism? What is scientism? Is talk about scientism bunk? Philistine? Cf. James Franklin, The Sokal Hoax .
5. Do most jurors suffer from the malady of mathematical or numerical illiteracy, from "innumeracy"? Most judges? Lawyers? If so, is it possible that innumeracy -- particularly the innumeracy of legal professionals -- is the real reason why the law refuses to express burdens of proof and persuasion in numerical terms? Or is there a better reason for the seeming antipathy to numbers in this part of our law?
E. Should our system of factual proof be cleansed of the pretense(?) that the quality and quantity of proof of facts are amenable to rational analysis? Should we expressly tell judges and jurors that their intuitions about evidence and facts should be their sole guide in their efforts to determine the facts?
1. Does it follow that we should prohibit all expert testimony?
2. Does it follow that we should prohibit all mathematical evidence (including, e.g., statistical evidence in employment discrimination litigation)?
All sorts of edibles and inedibles are mushed up in the pottage of "relevance." See Rethinking Relevancy.