INDUCTION, the name given to the logical process by which from a study of particular instances we arrive at a general principle or law.  The term is also applied to an electric or magnetic effect produced without direct contact and equal to the cause, being essentially its reproduction.

INDULGENCE, remission by Church authority of the guilt of a sin on the penitent confession of the sinner to a priest, which, according to Roman Catholic theology, the Church is enabled to dispense out of the inexhaustible treasury in reserve of the merits of Christ.

INDUS, a great river of India, 1800 m. long; rises in Thibet, on the N. of the Himalayas, flows NW. through Cashmere, then SW. through the Punjab and Sind to the sea; its upper course is through great gorges and very rapid, but after the entrance of the Kabul River its way lies through arid plains, and it is navigable; after receiving the Panjnad its volume decreases through evaporation and the sinking of some of the many streams into which it divides in the sand; on one of the branches of the delta stands the thriving port of Kurrachee.

INERTIA, that property of bodies by which they remain in a state of rest or of motion in a straight line till disturbed by a force moving them in the one case or arresting them in the other.

INEZ DE CASTRO.  See CASTRO.

INFALLIBILITY, freedom from all error in the past and from all possibility of error in the future as claimed by the Church of Rome.  This claim extends to all matters of faith, morals, and discipline in the Church, and is based on an interpretation of Matt. xvi. 18, xxviii. 19; Eph. iv. 11-16, and other passages.  It is held that the Church is incapable of embracing any false doctrine from whatever quarter suggested, and that she is guided by the Divine Spirit in actively opposing heresy, in teaching all necessary truth, and in deciding all relative matters of controversy.  Infallibility is not claimed in connection with matters of fact, science, or general opinion.  The seat of infallibility has been much disputed even in the Roman Catholic Church itself, and the infallibility of the Pope was only decreed so recently as the Vatican Council in 1870.  It was always agreed that where the Pope and Bishops were unanimous they were infallible, and their unanimity might be expressed either in a general council, or in a decree of a local council tacitly accepted by the Pope and the rest of the Church, or even in a decree of the Pope alone if the bishops either expressly or tacitly affirmed it.  But the Vatican Council decided “that when the Roman Pontiff speaks ex cathedra—­that is, when he, using his office as pastor and doctor of all Christians, in virtue of his apostolic office, defines a doctrine of faith and morals to be held by the whole Church—­he by the Divine assistance, promised to him by the blessed Peter, possesses that infallibility with which the Divine Redeemer was pleased to invest His Church in the definition of doctrine in faith or morals, and that therefore such definitions of the Roman Pontiff are irreformable in their own nature and not because of the consent of the Church.”  The Greek Church puts forward a moderate claim to inerrancy, holding that as a matter of fact those councils which she regards as oecumenical have not erred in their decrees affecting faith and morals.