Webster's Dictionary 
(1): ( n.) As opposed to idealism, the doctrine that in sense perception there is an immediate cognition of the external object, and our knowledge of it is not mediate and representative.
(2): ( n.) Fidelity to nature or to real life; representation without idealization, and making no appeal to the imagination; adherence to the actual fact.
(3): ( n.) As opposed to nominalism, the doctrine that genera and species are real things or entities, existing independently of our conceptions. According to realism the Universal exists ante rem (Plato), or in re (Aristotle).
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
is a distinct and readily apprehended doctrine in the higher ranges of metaphysics, characterizing the whole scheme of speculation with which it may be associated. A Realist is one who maintains this doctrine. Realism asserts that General Terms, or Ideas, as they are called by Plato, such as Man, Horse, Plant, have a substantive, or real, existence independent of their actual and individual manifestations. This dogma early encountered opposition, which became so violent in the 12th and ensuing centuries as to distract philosophy, and to excite controversies that disturbed creeds and kingdoms, and that still survive, though in disguised forms and with greatly diminished virulence. The war of words frequently proceeded to blows and slaughter. Excommunication often attended the less popular side. Tracts, pamphlets, and formidable volumes were sustained or resisted with carnal and sanguinary weapons. Communities were divided by the bitter logomachy into hostile factions. The Church swarmed with discords. Universities were arrayed against each other, or were torn by intestine dissensions. Cities were opposed to cities; states to states; one religious order to another; and the conflict between the temporal and spiritual sovereignty was exacerbated and widened by the metaphysical strife. Brucker, and multitudes less cognizant than he of the influence of metaphysical conclusions on the condition and conduct of governments and societies, have superciliously sneered at these envenomed and long- enduring contentions, as merely the blind sophistries of men bewildered by vain abstractions or futile fantasies. But a philosophical problem which has remained unsolved for thousands of years, which engrossed and embattled the most acute intellects for centuries, and which has not yet ceased to produce perplexity and division; which enlisted the zeal alike of the scholar and the people, the priest and the prince, can be regarded as frivolous only by those who fail to discern the intellectual forces and associations by which the progress of the world is moulded. Sir William Hamilton, indeed, doubts the continued existence of any Realist doctrine, and regards it "as curious only in a historical point of view;" but this opinion apparently results from inattention to the transformations which speculative tenets undergo, and to the vitality of old doctrines through the instrumentality of new disguises. There is a true metempsychosis of metaphysical questions:
"Nec manet nt fuerat, nec formas seivat easdem,
Sed tamen ipsa eaden est: aaniam sic sc emper candem
Esse, sed in varias dooceo misaree figuras."
Sir William Hamilton's scant notices of Realism and Nominalism are ingenious, subtle, delicate, but they want compass, completeness, and depth. Twin-born with Realism was Nominalism (q.v.), its direct opposite, which strenuously denies the reality of General Terms, and maintains that they are names only, logical entities, convenient artifices of expression (nomidna mera, voces nudce, flatus vocis, articulated air, "vox et praeterea nihil"). Springing, as these antagonist views do, from the weakness of the human mind, which is unable to comprehend the primordial origin of being, and which is inevitably inclined to consider its imperfect knowledge complete and conclusive, the opposition began with the beginning of systematic speculation, accompanied its development, and acquired predominance in the ages characterized by dialectical earnestness and verbal precision. The contradictory tenets were upheld by rival sects of Hindui philosophers; they produced a wide severance of opinion in the brightest aera of Greek philosophy; they remained irreconcilable, though at times indistinct, in the schools of Alexandria: they burst out into clamorous fury in the Middle Ages, when the loftiest intellects were employed in laying the foundations of systematic theology and of orthodox expression.
Between the extreme and contradictory schemes of Realism and Nominalism was interposed, chiefly by the keen perspicacity of Abelard, but in accordance with the probable views of Aristotle. a doctrine of compromise which has been designated Conceptualism. The Conceptualist theory holds that General Notions, or Universals, have a real existence in individuals, but no real or substantial being without them. It recognises their positive existence in the mind, which derives them by abstraction and generalization from particulars, and employs them as the signs or names of the classes of concrete realities to which they are applicable. The Realist doctrine is that, before Socrates, Plato, and Phedo, or any other individual men existed, Man, as an abstract idea, had an essential and immutable reality, and that Socrates, Plato, and Phaedo were men solely in consequence of possessing this ideal manhood — Κατά Μέθεξιν . The Nominalist, on the other hand, alleged that humanitv existed only in Socrates, Plato, Phaedo, and other individuals; that the term was only an intellectual device for indicating the common properties characteristic of Socrates, Plato, and Phaedo by giving them the general name Man, and thus embracing them in one class. The Conceptualist agreed with the Nominalist in refusing anl absolute existence to the general term Man, and in assigning to it a Real existence only in conjunction with Socrates, Plato, Phnedo, etc., but he endeavored to satisfy the demands of the Realist by admitting that the conception Man, attained by abstraction and generalization from individuals, had an actual existence, and was an intelligible reality in the mind apprehending it. Thus Abelard was antagonist at once to William of Champeaux and to Roscellinus. Employing the quaint but precise language of the schoolmen, the idealists held universalia esse ante rem; the Nominalists, universalia esse post rem; the Conceptualists of various types, universalia esse in rem. To the last should be added et etiam in intellectu. These distinctions may appear shadowy and impalpable, but metaphysics dwells amid such "airy shapes," and these have had a marked influence and serious consequences in politics, law, morals, philosophy, and religion: "inclusas animas, superumque ad lumen ituras."
Nominalism has already met with due consideration. (See Nominalism). The present notice will consequentlv be confined to Realism, except so far as Nominalism and Conceptualism may be inextricably entwined with it.
I. Origin Of Realism . — It would be misplaced industry, and inconsistent with the brevity required here, to investigate the Realist doctrines which were entertained and developed in the philosophy of the Hindus. But the mediaeval dogma is so intimately connected with the tenor of Greek speculation that a reference to its remote source in the schools of Athens cannot be avoided. The controversy between Realism and Nominalism did not become predominant in speculation till the close of the 11th century, but the antagonism was distinctly declared from the times of Plato and Aristotle. The wide differences which separated the schemes of the great teacher and his greater pupil in their explanation of the intelligible universe ( Mundus Intelligibilis ) were plainly manifest to the successors of those great heresiarchs. The doctrine of Plato and the earnest opposition of Aristotle may be best appreciated by the careful consideration of the multitudinous passages in the text of Aristotle referred to in the index of Bonlitz (Aristotelis Opera [ed. Acad. Berolin.], vol. iv) under the head of "Plato, 2." Evidences not merely of the continued antagonism of the Academic and Peripatetic schools, but also of the recognition of the gravity and the consequences of this antagonism, are abundant in the subsequent ages. It may suffice to refer to Plotinus (Emnnead. III, 9:1; V, v, 1; IX, 3:10), to a passage in Porphyry, which will soon require to be cited, and to Hesychius Milesius (Fr. 7, ii, 53, Fragm. Histor. Grasc. 4:173), who has stated clearly and precisely the Platonic thesis ( ῎Εστυ Δὲ Τῶν Εἰδῶν '''''Ž''''' '''''Ν''''' Ἕκαστον Αϊ v Διόν Τε Καὶ Νόημα Καὶ Πρὸς Τούτοις Ἀπαθές . Διὸ Καί Φησιν Ἐν Τῇ Φύσει Τὰς Ἰδεάς Ἐστάναι Καθάπερ Παραδείγματα , Τὰ Δ᾿ Ἄλλἀ Ταύταις Ἐοικέναι , Τούτων Ὁμοιώματα Καθεστῶτα ) . But the divergence of the schools in regard to Universals, or genera generalissima, and to abstract notions generally, remained an indeterminate disputation in the Hellenic world, and was not raised to supreme importance till it passed, in the mediaeval period, from transcendental ontology to dialectics and theology. The germ of the grand debate is found in one of the associates of the Neo-Platonic schools, but it scarcely vegetated till the scholastic period. Porphyry had said, in his introduction to the Categories of Aristotle (Schol. Aristot. ap. Aristot. Opera [ed. Acad. Berlin.], 3:1), that he would abstain from the more recondite inquiries, and aim only at a concise presentation of the simpler topics. "For," he proceeds, "I will decline to speak of the essential character of genera and species, or to inquire whether they are substantially corporeal or incorporeal, and whether they are separable or existent only in perception, since this is a most profound investigation, and requires other and deeper examination."
The Greek of Porphyry was almost entirely unknown to mediseval speculators, but the Latin paraphrase of Boethius was familiar to them, and constituted, as it were, a text-book of elementary logic. Thus the question of the nature of Universals was distinctly raised, and the opposite views which were entertained on the subject divided reasoners into hostile camps, and led to those passionate controversies which have been already alluded to. It was only gradually, however, that the opposition became clear and well marked, and connected itself closely with the gravest interests that have occupied the minds of men. In the first half of the 9th century, Rabanus Mnaurus, commenting on the text of Porphyry just quoted, but using the version of Boethius, recognises the conflict of opinion (Cousin, Introd. aux OEuvres Inedits d'Abelard, p. 77), and is supposed to have inclined to the Nominalistic side (Caraman, Hist. des Rev. de lac Philosophie, i, 249). It would probably be more correct to conclude that he sought a ground of conciliation between the two extremes. The difficult problem was, however, brought forward into distinct contemplation. If there was any tendency in Rabanus Maurus to what was atterwards known as Nominalism, the reaction showed itself promptly. In the next generation, the philosophy of Johannes Scotus Erigena, which was founded on an imperfect acquaintance with the Neo- Platonic teachings, ran into decided Pantheism, in accordance with the results of those teachings, as developed by Plotinus. Regarding God as the source whence all things proceed, by which all things are sustained, and to which all things return — representing creation as the self-evolution of the Creator, and destruction as the self-reabsorption, he rendered God all things and all things God. The basis of his whole scheme was involved in the Platonic theory of ideas, (See Platonic Philosophy), and in the Realist tenet Universallia Ante Rem. Not merely were the body and spirit of Scotus's philosophy heterodox, but it contained several particular conclusions which were deemed heretical, and which provoked the ecclesiastical censure which thev received.
The Pantheistic doctrines of Scotus Erigena naturally excited opposition when the results to which they led became apparent. If God wrere all things, then necessarily all things would be essentially God — being the external and phenomenal manifestations of the divine activity, and constituting, at the same time, the divine essence, inasmuch as their whole support was a real existence in the divine substance. It is the inevitable tendency of a metaphysical dogma to be unfolded by its acolytes into its ultimate logical consequences, which reveal the extravagances and the hazards of the position. It is the inevitable tendency of such revelation to arouse antagonism, and to suggest security in the opposite extreme. By such oscillation between contradictory tenets, the humnan intellect is kept from stagnation, and research and meditation are constantly stimulated. The Pantheism of Scotus Erigena annihilated independent individual existence and individual responsibility; and it obliterated the distinction between the Creator and the creation. The refutation of his errors was sought in the cxamination and denial of his premises, as well as in the repudiation of his conclusions. His views had been founded on the supposititious writings of Dionysius the Areopagite, which wrere steeped in Neo-Platonism (q.v.). Their antidote was expected from the school of Aristotle, whose logical opinions were gradually disseminated throughout Western Europe, through, Saracenic and Jewish channels, and which had been partially known throutgh Boethius during nearly all mediaeval times.
But the latter part of the 9th, the whole of the 10th, and most of the 11th century were eminently unfavorable to diligent study and tranquil speculation. It was the period of Arab ravage and encroachment in the Eastern Empire; the period of the ruthless descents of Danes and Northmen in the Western; the period when the reigning dynasties of France and England were changed; when Italy was distracted by invasions and by wars between contending emperors; and when the fierce strife between the secular and spiritual authority became peculiarly acrimonious. As the result of these wide-spread disturbances. discord and anarchy, lawlessness and rapine, general wretchedness and insecurity prevailed. Two centuries thus elapsed before the great question of Universals distinctly emerged out of the earlier discordances of opinion. Towards their conclusion, a purely theological question had arisen, which recalled eager inquiry into the nature of Universals. This was the denial of transubstantiation by Berengarius on grounds which implied Nominalism.
About the same time, the doctrine of Nominalism was explicitly asserted by Roscellinus, a canon of Compiegne. He has been usually regarded as the founder of the sect, but may have been preceded by his master, Johannes Surdus (John the Deaf), of whom very little is known. Roscellinus held that ‘ "geenerat and species are not realities, but only words denoting, abstractions;" that, consequently, "there are no such things as universals, but only individuals." Realism is thus directly contradicted. These speculations pointed towards dalngerous heresies in theology. Roscellinus, denying all but individual existences, assailed the unity of persons in the Trinity, and thus maintained Tritheism. The Church was at once aroused. Numerous confutations were propounded, the most celebrated of which was the tractate of Anselm, archbishop of Canterbury, De Fide Trinitatis. Anselm holds the Realist doctrine of Universals, and is occasionally betrayed into extravagance. His polemics is, however, theological rather than dialectical or metaphysical. He attacks perilous errors in religious beliet; and assails speculative opinions only incidentally. Remusat, while considering him a decided Realist, deems that his prominence in the controversy between Realism and Nominalism has been exaggerated (Remusat, St. Anselme, pt. ii, ch. 3:p. 494). Efforts were made to reconcile the conflict between the discordant doctrines. but they only rendered the issue and the antagonism more pronounced. William de Champeaux (De Campbellis) held that "the Universal or genus is something real; the individuals composing the genus have no diversity of essence, but only of accidental elements." This is the first precise asseveration of Realism in medineval philosophy. With William de Champeaux the essence of things is ascribed to the genera, the individual is reduced to a simple accident. With Roscellinus, the individuals alone exist, and they constitute the essence of things. With Champeaux, the essence of things is in the genera to which they belong, for so far as they are individuals they are only accidents" (Caraman, Hist. des Rev. de la Philippians vol. ii, ch. ii, p. 48).
Thenceforward the great controversy proceeds with increasing ardor, and furnishes the battle-field for the rival schools and rival schoolmen of the Middle Ages. The further consideration of these dissensions belongs, however, more appropriately to the discussion of the development of scholasticism. (See Scholasticism).
II. Nature Of Realism. — The general character of Realism has been exhibited sufficiently to render its origin and evolution intelligible. A fuller explanation is needed to enable us to understand the importance which it assumed in medineval speculation. Cicero has said that "there is nothing so absurd as not to have been maintained by some of the philosophers." It is easier to ridicule than to appreciate the reveries of philosophy. The aberrations of metaphysics and the paradoxes of dialectics are only the zealous and inadequate expression of far-reaching truths imperfectly apprehended. We certainly should not complain of either the excesses or the blindness of the schoolmen, in an age which is inclined to accept protoplasm as a sufficient explanation of all life, and evolution as a complete exposition of creation, or a substitute for it. Yet, even in these cases, much is charged upon the hierophants which they do not accept as part of their doctrines. Realism was the mediaeval and dialectical reproduction of the Platonic ideas. It asserted that general terms, such as Man, Horse, Tree, Flower, etc., were not merely logical devices, creatures of abstraction, ingenuities of language, but were realities, separable ( Χωριστά ) from the being of individual Men, Horses, Trees, Flowers, etc. In Plato and the Platonic school these ideas were supposed to have a real, primordial, changeless, and eternal existence in the Divine Mind, as the archetypes of all things that are made. It demands no extraordinary range of intellect to point out the presumption of attempting to determine the contents of the Divine Mind and the modes of its procedure in ordering the creation.
It needs no great intellectual effort to dilate upon the practical incongruities of representing Socrates as a transitory accident; having no real existence except so far as he partakes of the one, universal, ideal Man, who is immortal, incorporeal, immaterial, and unchangeable; communicated and communicable to all men, past, present, and fuiture; completely contained in each, yet abundant for all, and independent of each and of all. These objections blink or evade the subtleties of the problem. These sneers do not reach the difficulty with which the greatest philosophers have struggled, and struggled in vain. No doubt our knowledge of generatls and specials is attained (so far as the human mind is capable of ascertaining the process of attaining knowledge) by abstraction from individual things observed, and by recombination of their accordant characteristics. No doubt the abstract terms, so arrived at, are the instruments of linguistic and logical classification, which we employ unsuspiciously in reasoning and conversation. But is this all? Is this a complete solution of the enigma? Is it not a mere screen which conceals the real enigma from us? There is a general, not an individual, resemblance between all men — homo simillimus honzini — nihil similius hominii quam homo. They are alike in consequence of their participation in a common humanity.
Our knowledge of this humanity may be — must be — derived by generalization from the common characteristics of all men. But, again, it should be asked, Is this all? Does our knowledge precede or follow this possession of a common humanity? Does it do anything more than recognise its presence? How does the common humanity come into existence? How does it continue in existence? How is it to be interpreted? Is there no plan or order in creation? No eternal design in the purposes of the Creator? Is everything spasmodical, momentary creation, with observance of antecedent forms? Whence, then, such observance, and the maintenance of uniformity, and all the characteristics of preordination? How does it occur that the earth proceeds ever to "bring forth the living creature after his kind, cattle and creeping thing, and beast of the earth after his kind," if the several kinds and genera and species are mere abstractions, pure figments of the generalizing faculty? Did this unvarying observance of the type arise, without any reality of the type, by the accidental collision of atoms in all the infinite variety of their hypothetical contacts, and by survival of the fittest, through self-adaptation to their shifting surroundings? No permanent forms, transmitted from generation to generation, from age to age, could thus be maintained. The unmitigated repudiation of Realism leads straight to the acceptance of the creed of Lucretius and Darwin and Herbert Spencer.
Nam certe neque consilio Primordia rerum Ordini se quaeque, atque sagaci menite locarnnt: Nec quos qneque darent motus pelpise e ilrofecto; Sed qnia mnulltimnodis, mnultis, mutatal, per Omne Ex infillito vexantur percita plagis, Omne genus motus, et coetus experinmlo, Tandem devenient in taleis dispositnras, Qualibus hec rebus consistit summa cieata; Et multos etiam magnos servata per mannos, Ut semel in motus conjecta ‘ st convenieuteis." The answer of the Epicurean herd will not solve the riddles proposed. Realism offered a very different solution, which, however inadequate and unsatisfactory it may be deemed, did not affect to treat the questions as shallow or unimportant. But may there not be some genuine truth, obscured, disguised, mutilated, lame, yet, nevertheless, struggling into meaning, in the theory of Realism? Is there not a plan, a divine order, throughout all creation? Are there not types — intelligible, potential, not actual types — to be accounted for? Has a conception of the reason — never varying, but persisting as long as the reason and the objects of reason endure — has such a conception a less real existence than the concrete and material, or individual forms which correspond to the conception, but which are changing at all times during their existence, and are born to perish? The existence is of very different character, but is it less truly existence? The ambiguity and vagueness of their terms may not hiave been recognised by the mediaeval Idealists and Idealists. Are they always clearly apprehended by their critics? Have the censors of Realism filly appreciated the incomprehensibility and variability of the Realist doctrine without loss of its distinctive character and without sacrifice of its essential tenet? Doubtless the theory of Realism was indistinct, not rigorously determined, and scarcely palpable. Doubtless the modes of its statement were obnoxious to grave exceptions, and led to misapprehensions and misconceptions on the part even of its advocates. The subjects with which the theory dealt may very well lie beyond any determinate grasp of the human faculties. But an earnest effort was made to interpret the great mysteries of existence — the permanence of type, with the variability and fragility of all embodiments of the type. This world may be "all a fleeting show, for man's illusion given;" but is there nothing unseen behind it which is true, and which furnishes its unalterable patterns? There is some justification, or at least some elucidation, of the thesis of the Realists to be deduced from the conclusions of comparative anatomy. Aristotle taught that the skeletons of the beast, the bird, and the fish revealed a common type, with characteristic deviations (De Part. Animal.). Six centuries later, Lactantius, or the Pseudo-Lactantius, reproduced the same tenet in a remarkable passage: "Una dispositio, et unus habitus, innumerabiles imaginis proeferat varietates" (De Opific. Dei, c. vii). In our own day, the distinguished comparative anatomist Owen has demonstrated the validity of the conjecture of Aristotle by his work On the Achetypal Skeleton of Vertebrate Animals; and Dr. M'Cosh has given, perhaps without full recognition of its import, a most instructive application of the principle in his Typical Forms and Special Ends in Creation. Is there no truth, no validity, no reality in the types?
Is Realism, then, to be regarded as true? By no means. It only contains an element, an unsegregated element, of truth. It is a very important element, but it is dimly entertained and extravagantly expressed. Is its opposite, Nominalism, true? Again the answer must be, By no means. It contemplates only one side of the truth; runs into equal extravagance, and excludes utterly the indispensable particle of truth contained in the adverse doctrine. Is the truth attained by combining the antagonistic views? Not so. The two schemes cannot be united. and can scarcelv be reconciled, except by regarding them as imperfect expositions from opposite points of view. Moreover, two partial and fragmentary truths can never make the whole truth. Truth is a consistent. harmonious, organic whole. It can never be attained by dovetailing patches of truth, or by forming a mosaic.
Philosophy, in its development, is a series of erroneous and conflicting positions. One extreme provokes another extreme; but the conception of first principles. and the range of deductions from them, become enlarged and cleared with the progress and succession of errors, although the full and precise truth may never be reached.
The truth which seems to be involved in Realism is this: Universals, genera, species, represent the permanent forms of the intelligible creation. They attest a settled and regular order in the sensible universe. They reveal a preordained, or predetermined, plan in the several classes of existence; an enduring truth; an abiding uniformity in the midst of individual deviations and transitory manifestations; a design habitually fulfilled; types which subsist, though actualities vanish. A part, at least, of the error of Realism — for neither its whole truth nor its whole error can be distinctly grasped and perspicuously expressed — consisted in presenting these important conclusions in an exaggerated form, so that they contradicted the partial truth equally involved in Nominalism: that individuals have a real as well as an actual existence, and that the generic and specific terms which are habitually employed, and are indispensable in language, are modes of classifying our perceptions and conceptions, and are used altogether independently of any ulterior suggestions which may be implicated in them.
The Nominalist denied a metaphysical truth because it was not embraced within the sphere of his logical requiremnents. The Realist assailed the logical truth because it failed to embrace an ontological explanation, and appeared to be at variance with it.
Bitter contradictions and acrimonious hostilities necessarily resulted from the antagonism, in consequence of the inevitable association of the conflicting doctrines with adverse parties and interests in theology, in Church and in State.
III. Literature . — The historians of philosophy, who embrace the philosophy of the Middle Ages, necessarily pay much attention to Realism and Nominalism. More special sources of information are, Caraman, Hist. Des Revolutions De La Philosophie En Fransce; Baumgarten Crusius, De Vero Scholast. Retal. Et Nominal. Discrimine (Jena, 1821); Cousin, Fragments Philosophiques (Paris, 1840); id. Introd. Aux Ouvres Inedits D'Abelaurd; Exner, Nominatlismus Und Reallismus (Prague, 1842); Kohler, Realismus And Nominualismuits In Ihrem Ifuss Auf Die Dogmat. Syst. Des Mittelalt. (Gotha, 1857); Hautreau, Philosophie Scolastique (Paris, 1858); Cupely, Espirit De La Philosophie Scolastique (ibid. 1868). Much valuable suggestion may also be obtained from Rdmusat, Abelard (ibid. 1845, 2 vols.); id. St. Anselme (ibid. 1853). To these may be added, Emerson, Realism And Nominalism. (G. F. H.)
The Nuttall Encyclopedia 
As opposed to Nominalism, is the belief that general terms denote real things and are not mere names or answerable to the mere conception of them, and as opposed to idealism, is in philosophy the belief that we have an immediate cognition of things external to us, and that they are as they seem. In art and literature it is the tendency to conceive and represent things as they are, however unsightly and immoral they may be, without any respect to the beautiful, the true, or the good. In Ruskin's teaching mere realism is not art; according to him art is concerned with the rendering and portrayal of ideals.