Semantics of the Accepted Elements of Legal Malpractice

Descriptions of the cause of action “legal malpractice” and for similar professional torts, e.g., accountant, among others, use the phrases “reasonable and prudent,”
“reasonably prudent,” and “of ordinary prudence.”  For example, there are over 1200 uses of these phrases in Texas cases.These are longstanding formulations; their
uses are deeply embedded in custom; and they are tradition.*  In fact these are different, and they can constitute misleading
wording.  Their use in lawyer malpractice
cases is like that. (Since they are different, they can make a difference to legal argument, most significantly, oral arguments to juries.)

(What is the difference between tradition and custom.  Maybe something can be a custom without being a tradition.  Maybe traditions are necessarily longer than customs?  Perhaps one little activity can be a custom, but it be too small to be a tradition? I don’t think either of these is true.  I wonder what is?)

The reason is simple.  In the
context of evaluating lawyer performance the lawyer’s actions and omissions
must always be at least reasonable. 
What does it mean when it is said that they must also be “prudent”? The
word “prudence” can just means reasonable, in which case, their use together–one modifying the other–is
redundant.  It could mean “reasonably
looking after some affairs or other,” in which case, it still means nothing but
reasonable.  Or, it might mean what it usually
means, “That one is looking after what he does carefully while facing ‘forward’.”  This usage is again redundant. 

It must also be remembered that the word “prudent” has a whiff of
self-interest built into it. Thus, one is prudent when he is looking after his
own affairs in certain ways.  Obviously
that is a wrong idea in this context. L is not treating C as he is required to
do if, and to the extent, that he is looking after his own self interest. The idea of prudence also has breezes of the
ideas of restraint, caution, and conservative-ness built into it.   These may or may not be in C’s interests,
and certainly may not accord with his instructions.

It seems to me that an act can be customary (even across a large relevant group), and even be traditional, and yet not be prudent because of some new set of events or a new situation.  Lawyer decision-making is subject to changes like this, and not just from new statutes or court decision.  The situational or train-of-event changes could be social or economic; they could be known or unknown.

Problems arise for prudence.  Can an act be prudent but unreasonable.  I am inclined to doubt it, though I think the route the prudent action may not be reasonable.  The reasoning up to the decision to act (or refrain from acting) can be unreasonable and the decision itself can both be unreasonable, and then the act turn out to be prudent.