Presumption and burden of proof: is the side that must prove its case determined by the argument's logic, or merely by rhetorical advantage?

Richard Whately, answered from the texts and cited to the page.

The position in brief

A presumption is a pre-occupation of the ground. It does not assert that a proposition is antecedently more probable, only that it stands until sufficient reason is brought against it, and that the onus probandi lies on the party who would disturb it.12345

Sources

  1. ' ■ ^ • 1 Presumption out to the hearer, as occasion may serve, on which and burden side the presumption lies, and to which belongs ^^ pi'O'^f. the [onus probandi] hurdcii of proof.
    Elements of Rhetoric
  2. A body of troops may be perfectly adequate to the defence. of a fortress against any attack that may be made on it; and yet, if, ignorant of the advantage they possess, they sally forth into the open field to encounter the enemy, they may suffer a repulse. At any rate, even if strong enough to act on the offensive, they ought CH. III., 2.] CONVICTION. Ill still to keep possession of their fortress.
    Elements of Rhetoric
  3. The case of Episcopacy is exactly parallel; but Hooker seems to have overlooked this advantage: he sets himself to;prove the apostolic origin of the institution; as if his task 114 ELEMENTS OF RHETORIC. [PART I.
    Elements of Rhetoric
  4. No one is called on (though he may find it advisable) to defend an ex- isting institution, till some argument is adduced against it; and that argument ought in fairness to prove, not merely an actual inconvenience, but the possibility of a change for the better. Every book again, as well as person, ought to be pre- 112 ' ELEMENTS OF RHETORIC. [PART I. sumed harmless (and consequently the copyright onMSnc?.
    Elements of Rhetoric
  5. It may be added, tliat the deference due to the decisions of an assembly is sometimes, erroneously, transferred to those of some individual member of it; that is, it is sometimes taken for granted that what they have, jointly, put forth, is to be interpreted by what he, in his own writings, may have said on the same points.
    Elements of Rhetoric

Where the argument is made

  • Elements of Rhetoric I.3 (of presumption and the burden of proof), and its application throughout Part I

How the argument was received

The doctrine I regard as my own contribution, and I press it as governing every dispute whatever.