Ratiocination   
var.
Reasoning-power

Ratiocination

Commens
Digital Companion to C. S. Peirce
Ratiocination
var.
Reasoning-power
1893 | Grand Logic 1893: Division III. Substantial Study of Logic Chapter VI. The Essence of Reasoning | CP 4.38-39

St. Thomas Aquinas [Summa totius logicæ Aristotelis (Opusculum 48)] divides the operations of the Understanding in reference to the logical character of their products into
     Simple Apprehension,
     Judgment, and
     Ratiocination, or Reasoning. [—]

Ratiocination or reasoning produces inferences or reasonings, which are expressed by argumentations, as, ” I think, therefore I must exist,” “Enoch, being a man, must have died; and since the Bible says he did not die, not everything in the Bible can be true.”

1893 | Grand Logic 1893: Division III. Substantial Study of Logic Chapter VI. The Essence of Reasoning | CP 4.45

Ratiocination is defined by St. Thomas as the operation by which reason proceeds from the known to the unknown.

1895 | Short Logic | EP 2:11-12

Reasoning is the process by which we attain a belief which we regard as the result of previous knowledge. [—]

Again, a given belief may be regarded as the effect of another given belief, without our seeming to see clearly why or how. Such a process is usually called an inference; but it ought not to be called a rational inference, or reasoning. A blind force constrains us. [—]

The word illation signifies a process of inference. Reasoning, in general, is sometimes called ratiocination. Argumentation is the expression of a reasoning.

1913 | An Essay toward Improving Our Reasoning in Security and in Uberty | EP 2:464

Reasoning-power; or Ratiocination, called by some Dianoetic Reason, is the power of drawing inferences that tend toward the truth, when their premises or the virtual assertions from which they set out are true.