His pupil and disciple Thomas Aquinas (1227-1274) was the philosopher and recognized champion of the Christian Church. In 1879 Pope Leo XIII, while proclaiming that every wise saying, every useful discovery, by whomsoever it may be wrought, should be welcomed with a willing and grateful mind, exhorted the leaders of the Roman Catholic Church to restore the golden wisdom of St. Thomas and to propagate it as widely as possible for the good of society and the advancement of all the sciences. Certainly the genius of St. Thomas Aquinas seems comprehensive enough to embrace all science as well as all philosophy from the Christian point of view. According to him there are two sources of knowledge, reason and revelation. These are not irreconcilably opposed.

The Greek philosophers speak with the voice of reason. It is the duty of theology to bring all knowledge into harmony with the truths of revelation imparted by G.o.d for the salvation of the human race. Averroes is in error when he argues the impossibility of something being created from nothing, and again when he implies that the individual intellect becomes merged in a transcendental intellect; for such teaching would be the contrary of what has been revealed in reference to the creation of the world and the immortality of the individual soul. In the accompanying ill.u.s.tration we see St. Thomas inspired by Christ in glory, guided by Moses, St. Peter, and the Evangelists, and instructed by Aristotle and Plato. He has overcome the heathen philosopher Averroes, who lies below discomfited.

[Ill.u.s.tration: ST. THOMAS AQUINAS OVERCOMING AVERROeS]

The English Franciscan Roger Bacon (1214-1294) deserves to be mentioned with the two great Dominicans. He was acquainted with the works of the Greek and Arabian scientists. He transmitted in a treatise that fell under the eye of Columbus the view of Aristotle in reference to the proximity of another continent on the other side of the Atlantic; he antic.i.p.ated the principle on which the telescope was afterwards constructed; he advocated basing natural science on experience and careful observation rather than on a process of reasoning. Roger Bacon's writings are characterized by a philosophical breadth of view. To his mind the earth is only an insignificant dot in the center of the vast heavens.

In the centuries that followed the death of Bacon the relation of this planet to the heavenly bodies was made an object of study by a succession of scientists who like him were versed in the achievements of preceding ages. Peurbach (1423-1461), author of _New Theories of the Planets_, developed the trigonometry of the Arabians, but died before fulfilling his plan to give Europe an epitome of the astronomy of Ptolemy. His pupil, Regiomonta.n.u.s, however, more than made good the intentions of his master. The work of Peurbach had as commentator the first teacher in astronomy of Copernicus (1473-1543). Later Copernicus spent nine years in Italy, studying at the universities and acquainting himself with Ptolemaic and other ancient views concerning the motions of the planets. He came to see that the apparent revolution of the heavenly bodies about the earth from east to west is really owing to the revolution of the earth on its axis from west to east. This view was so contrary to prevailing beliefs that Copernicus refused to publish his theory for thirty-six years. A copy of his book, teaching that our earth is not the center of the universe, was brought to him on his deathbed, but he never opened it.

Momentous as was this discovery, setting aside the geocentric system which had held captive the best minds for fourteen slow centuries and subst.i.tuting the heliocentric, it was but a link in the chain of successes in astronomy to which Tycho Brahe, Kepler, Galileo, Newton, and their followers contributed.

REFERENCES

_The Catholic Encyclopedia._

J. L. E. Dreyer, _History of the Planetary Systems_.

_Encyclopaedia Britannica._ Arabian Philosophy; Roger Bacon.

W. J. Townsend, _The Great Schoolmen of the Middle Ages_.

R. B. Vaughan, _St. Thomas of Aquin; his Life and Labours_.

Andrew D. White, _A History of the Warfare of Science with Theology in Christendom_.

CHAPTER V

THE CLa.s.sIFICATION OF THE SCIENCES--FRANCIS BACON

The preceding chapter has shown that there is a continuity in the development of single sciences. The astronomy, or the chemistry, or the mathematics, of one period depends so directly on the respective science of the foregoing period, that one feels justified in using the term "growth," or "evolution," to describe their progress. Now a vital relationship can be observed not only among different stages of the same science, but also among the different sciences. Physics, astronomy, and chemistry have much in common; geometry, trigonometry, arithmetic, and algebra are called "branches" of mathematics; zoology and botany are biological sciences, as having to do with living species. In the century following the death of Copernicus, two great scientists, Bacon and Descartes, compared all knowledge to a tree, of which the separate sciences are branches. They thought of all knowledge as a living organism with an interconnection or continuity of parts, and a capability of growth.

By the beginning of the seventeenth century the sciences were so considerable that in the interest of further progress a comprehensive view of the tree of knowledge, a survey of the field of learning, was needed. The task of making this survey was undertaken by Francis Bacon, Lord Verulam (1561-1626). His cla.s.sification of human knowledge was celebrated, and very influential in the progress of science. He kept one clear purpose in view, namely, the control of nature by man. He wished to take stock of what had already been accomplished, to supply deficiencies, and to enlarge the bounds of human empire. He was acutely conscious that this was an enterprise too great for any one man, and he used his utmost endeavors to induce James I to become the patron of the plan. His project admits of very simple statement now; he wished to edit an encyclopedia, but feared that it might prove impossible without cooperation and without state support. He felt capable of furnishing the plans for the building, but thought it a hardship that he was compelled to serve both as architect and laborer. The worthiness of these plans was attested in the middle of the eighteenth century, when the great French _Encyclopaedia_ was projected by Diderot and D'Alembert. The former, its chief editor and contributor, wrote in the Prospectus: "If we come out successful from this vast undertaking, we shall owe it mainly to Chancellor Bacon, who sketched the plan of a universal dictionary of sciences and arts at a time when there were not, so to speak, either arts or sciences. This extraordinary genius, when it was impossible to write a history of what men knew, wrote one of what they had to learn."

Bacon, as we shall amply see, was a firm believer in the study of the arts and occupations, and at the same time retained his devotion to principles and abstract thought. He knew that philosophy could aid the arts that supply daily needs; also that the arts and occupations enriched the field of philosophy, and that the basis of our generalizations must be the universe of things knowable. "For," he writes, "if men judge that learning should be referred to use and action, they judge well; but it is easy in this to fall into the error pointed out in the ancient fable; in which the other parts of the body found fault with the stomach, because it neither performed the office of motion as the limbs do, nor of sense, as the head does; but yet notwithstanding it is the stomach which digests and distributes the aliment to all the rest. So that if any man think that philosophy and universality are idle and unprofitable studies, he does not consider that all arts and professions are from thence supplied with sap and strength." For Bacon, as for Descartes, natural philosophy was the trunk of the tree of knowledge.

Human Learning (Bacon's Cla.s.sification)

Column Key: (A) Reason Philosophy, or the Sciences (B) Imagination Poesy (C) Memory History

--------------------------------------------------------------------------- Philosophia prima, or sapience -----+---+--------+----------------------+--------------------------------- (A) | | | Civil Philosophy | Intercourse | N | | (Standards of | Business | a | | right in:) | Government | t | Man +---------------+------+--------------------------------- | u | | Philosophy | Body | Medicine, Athletics, etc.

| r | | of Humanity +------+--------------------------------- | a | | (Anthropology)| | Logic | l | | | Soul | | | | | | Ethics | P +--------+-------------+-+------+--------+----------+------------- | h | | | Physics | Concrete | | i | | | (Material and | | M | l | | | Secondary | Abstract | a | o | | | Causes) | | t | s | Nature | Speculative | | | h | o | | | Metaphysics | Concrete | e | p | | | (Form and Final | | m | h | | | Causes) | Abstract | a | y | +-------------+-----------------+----------+ t | | | | Mechanics | i | | | Operative | | c | | | | Purified Magic | s | +--------+-------------+----------------------------+------------- | | G.o.d | Natural Theology, Nature of Angels and Spirits +---+--------+-------------------------------------------------------- | Divinity | Revelation -----+------------+-------------------------------------------------------- (B) | Narrative, or Heroical | Dramatic | Parabolic (Fables) -----+-----------+------------------------+-------------------------------- (C) | | Political | Memorials | Civil | (Civil History proper) | Antiquities | | | Perfect History | +-----------+------------+-------------------------------- | | | Learning | | Literary | | | | Arts | +-----------+--------------------------------------------- | | Ecclesiastical +-----------+-------------------+-------------------+----------------- | | Bonds | Arts | Mechanical | | (Control by Man) | | Experimental | +-------------------+-------------------+----------------- | | Errors | Pretergenerations | Natural | (Anomics) | (Monsters) | +-------------------+---------------+--------------------- | | Freedom | Generations | Astronomical Physics | | (Nomic Law) | | Physical Geography | | | | Physics of Matter | | | | Organic Species -----+-----------+-------------------+---------------+---------------------

------------+---------------------------------------------------- | Knowledge Cla.s.sified (Hugo of St. Victor, d. 1141).

------------+---------------------+------------------------------ Theoretical | Theology | | Natural Philosophy | | (Physic) | ------------+---------------------+------------------------------ | Mathematics | Arithmetic | | Music (study of harmony) | | Geometry | | Astronomy ------------+---------------------+------------------------------ Practical | Ethics, or individual morality (Moral) | Economics, or family morality | Politics, or civics ------------+---------------------------------------------------- Mechanical | Weaving, spinning, sewing; work in wool, flax, etc.

| Equipment--arms, ships; work in stone, wood, metal | Navigation | Agriculture | Hunting, fishing, foods | Medicine | Theatricals--drama, music, athletics, etc.

------------+---------------------------------------------------- Logical | Oratory | Grammar | Dialectic | Rhetoric ------------+----------------------------------------------------

On the other hand, he looked to the arts, crafts, and occupations as a source of scientific principles. In his survey of learning he found some records of agriculture and likewise of many mechanical arts. Some think them a kind of dishonor. "But if my judgment be of any weight, the use of History Mechanical is, of all others, the most radical and fundamental towards natural philosophy." When the different arts are known, the senses will furnish sufficient concrete material for the information of the understanding. The record of the arts is of most use because it exhibits things in motion, and leads more directly to practice. "Upon this history, therefore, mechanical and illiberal as it may seem (all fineness and daintiness set aside), the greatest diligence must be bestowed." "Again, among the particular arts those are to be preferred which exhibit, alter, and prepare natural bodies and materials of things as agriculture, cooking, chemistry, dyeing; the manufacture of gla.s.s, enamel, sugar, gunpowder, artificial fires, paper and the like." Weaving, carpentry, architecture, manufacture of mills, clocks, etc. follow. The purpose is not solely to bring the arts to perfection, but all mechanical experiments should be as streams flowing from all sides into the sea of philosophy.

Shortly after James I came to the throne in 1603, Bacon published his _Advancement of Learning_. He continued in other writings, however, to develop the organization of knowledge, and in 1623 summed up his plan in the _De Augmentis Scientiarum_.

A recent writer (Pearson, 1900) has attempted to summarize Bacon's cla.s.sification of the different branches of learning. When one compares this summary with an outline of the cla.s.sification of knowledge made by the French monk, Hugo of St. Victor, who stands midway between Isidore of Seville (570-636) and Bacon, some points of resemblance are of course obvious. Moreover, Hugo, like Bacon, insisted on the importance of not being narrowly utilitarian. Men, he says, are often accustomed to value knowledge not on its own account but for what it yields. Thus it is with the arts of husbandry, weaving, painting, and the like, where skill is considered absolutely vain, unless it results in some useful product.

If, however, we judged after this fashion of G.o.d's wisdom, then, no doubt, the creation would be preferred to the Creator. But wisdom is life, and the love of wisdom is the joy of life (_felicitas vitae_).

Nevertheless, when we compare these cla.s.sifications diligently, we find very marked differences between Bacon's views and the medieval. The weakest part of Hugo's cla.s.sification is that which deals with natural philosophy. _Physica_, he says, undertakes the investigation of the causes of things in their effects, and of effects in their causes. It deals with the explanation of earthquakes, tides, the virtues of plants, the fierce instincts of wild animals, every species of stone, shrub, and reptile. When we turn to his special work, however, on this branch of knowledge, _Concerning Beasts and Other Things_, we find no attempt to subdivide the field of _physica_, but a series of details in botany, geology, zoology, and human anatomy, mostly arranged in dictionary form.

When we refer to Bacon's cla.s.sification we find that Physics corresponds to Hugo's _Physica_. It studies natural phenomena in relation to their material causes. For this study, Natural History, according to Bacon, supplies the facts. Let us glance, then, at his work on natural history, and see how far he had advanced from the medieval toward the modern conception of the sciences.

For purposes of scientific study he divided the phenomena of the universe into (1) Celestial phenomena; (2) Atmosphere; (3) Globe; (4) Substance of earth, air, fire, water; (5) Genera, species, etc. Great scope is given to the natural history of man. The arts are cla.s.sified as _nature modified by man_. _History_ means, of course, descriptive science.

_Bacon's Catalogue of Particular Histories by t.i.tles (1620)_

1. History of the Heavenly Bodies; or Astronomical History.

2. History of the Configuration of the Heavens and the parts thereof towards the Earth and the parts thereof; or Cosmographical History.

3. History of Comets.

4. History of Fiery Meteors.

5. History of Lightnings, Thunderbolts, Thunders, and Coruscations.

6. History of Winds and Sudden Blasts and Undulations of the Air.

7. History of Rainbows.

8. History of Clouds, as they are seen above.

9. History of the Blue Expanse, of Twilight, of Mock-Suns, Mock-Moons, Haloes, various colours of the Sun; and of every variety in the aspect of the heavens caused by the medium.

10. History of Showers, Ordinary, Stormy, and Prodigious; also of Waterspouts (as they are called); and the like.

11. History of Hail, Snow, Frost, h.o.a.r-frost, Fog, Dew, and the like.

12. History of all other things that fall or descend from above, and that are generated in the upper region.

13. History of Sounds in the upper region (if there be any), besides Thunder.

14. History of Air as a whole, or in the Configuration of the World.

15. History of the Seasons or Temperatures of the Year, as well according to the variations of Regions as according to accidents of Times and Periods of Years; of Floods, Heats, Droughts, and the like.

16. History of Earth and Sea; of the Shape and Compa.s.s of them, and their Configurations compared with each other; and of their broadening or narrowing; of Islands in the Sea; of Gulfs of the Sea, and Salt Lakes within the Land; Isthmuses and Promontories.