Amendment IV, Bill of Rights, US Constitution

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

The language of the Bill of Rights is sparse, based on intuitive ideas of precedent and definition in English law at the time of the Revolution, and somewhat loose, perhaps frustratingly so.

For example, after years of disagreement, the Second Amendment has been read so as to allow for individual firearms ownership.  (Incidentally, I believe that the underlying argument of the Supreme Court in Heller and McDonald v. Chicago is weak and uncompelling, but the Court’s holdings are correct, based upon certain ways of understanding rights that are fairly unexplored.)

What does a reasonable search mean?  What is probable cause?

I suggest that these two terms have drifted over time along with common usage, in a way that erodes the protections of the right.

Nowadays, people might say that a reasonable search is one for which a reason can be conceived by the person suggesting the search – exercising the faculty of classification, inference, and deduction to formulate the initiative to proceed, rather than acting on a whim.

Similarly, most people might think probable cause is that it is more likely than not that a suggested cause, or reason to proceed, is valid rather than invalid.  The principle of probability in mathematical statistics voices this interpretation.  A heuristic gathering of all ideas about something makes it likely, or unlikely; and if it is likely, it would be called a probable cause.

I suggest that both of these definitions are deviations from the original intent as used during the writing of the Bill of Rights.  A reasonable search (or unreasonable search) should not balance upon the presence or absence of the subjective reasoning powers of the proponent of the investigation.  Rather, there would be objective rules of thumb that allows for an affirmation that most people would concur that the reason is valid, not that it is conceivable.

Even more significantly, probable cause should not be married to mathematical principles of probability.  The mathematical use of the term was apparently not even in existence when the Bill of Rights was written.  Rather, an objective and PROBATIVE sequence – a causal chain of events – must be offered to create a PROBABLE CAUSE, aka PROBATIVE CAUSE.

Does this person have illicit drugs in their house?  Is there an orderly sequence of objective events and findings that, if fact, prove the presence of that thing to be seized within the private place meriting investigation.  “Looking like a druggie” is a substantive element of contributor to heuristic likelihood that illicit drugs are present in the house; but is immaterial in a probative chain of causation.

Our utilitarian and instrumental approach to reason allows us to gloss over the difference between probative and likely causes; and between reasonable or logically consistent bases for searches.  In review, the current instrumental approach blunts the protections upheld by the various rights.