Proving responsibility in personal injury cases can be reduced to the following: a brick by itself is a brick but together bricks make a wall. Essentially that is the definition of relevant evidence.
Relevant evidence, according to the Federal Rules of Evidence, means that it has a tendency to make any fact more or less probable than it would be without the evidence. Each state, including Massachusetts where I practice, follows that definition.
The above reference to bricks is contained in the Advisory Committee’s Note to Federal Rule of Evidence 401. The Congress, the drafters of the Federal Rules, use another analogy, one close to baseball-mad Boston. “It is not supposed that every witness can make a home run.”
I might have said it differently. I would have used “hit” a home run instead of “make” a home run. Then again, as my father who founded our law firm used to say, “Let’s get a hit!” Yes, not every witness can hit a home run but make sure the witness can get a base hit.