In his philosophy the universe is divided into the celestial region of ideas and the mundane region of material phenomena, answering to the modern conception of heaven and earth. As the phenomena of matter are but copies of ideas (not, as some suppose, the bodily realisation of them), there arises a question: How do ideas become matter? Plato gives two different explanations. In the "Republic" he says that G.o.d, instead of perpetually creating individual things, created a distinct type (idea) for each thing, and from this type all objects of the cla.s.s are made. But in a later work, the "Timaeus," Plato takes another view of the origin of the world. Types are conceived as having existed from all eternity, and G.o.d, in fashioning cosmos out of chaos, fashioned it after the model of these eternal types.
Plato"s conception of heaven and earth as two distinct regions is completed by his conception of the double nature of the soul; or, rather, of two souls, one rational and the other sensitive. The sensitive soul awakens the divine reminiscences of the rational soul; and the rational soul, by detecting the One in the Many, preserves man from the scepticism inevitably resulting from mere sense-knowledge.
Aristotle, who was born in 384 B.C., was Plato"s pupil. He, however, completely broke away from his master"s theory. He maintained that individual objects alone exist. But if only individual objects exist, only by the senses can they be known; and if we have only sense-knowledge, how can we arrive at the general truths on which both philosophy and science are founded? This was the problem which had led Plato to claim for ideas, or types of general truths, a higher origin than the intermittent and varying data of the senses.
Aristotle held that it could be solved in a natural way without the conception of an ideal world. In his view, ideas were obtained by induction. Sensation is the basis of all knowledge. But we have another faculty besides that of sensation; we have memory. Having perceived many objects, we remember our perceptions, and this enables us to discern wherein things differ and wherein they agree. Then, by means of the art of induction, we arrive at ideas. Aristotle"s theory of induction is clearly explained by him: "Experience furnishes the principles of every science. Thus astronomy is grounded on observation. For if we were to observe properly the phenomena of the heavens, we might demonstrate the laws which regulate them. The same applies to other sciences." Had he always held before his eyes this conception of science, he would have antic.i.p.ated Bacon--he would have been the Father of Positive Science.
But he could not confine himself to experience, as there was not sufficient experience acc.u.mulated in his age from which to generalise with any effect. So he turned to logic as an instrument for investigating the mystery of existence, and by bringing physics and metaphysics together again, he paved the way for a new era--the era of scepticism.
All the wisdom of the ancient world was powerless against the sceptics.
Faith in truth was extinct; faith in human nature was gone; philosophy was impossible. And, though the influence of Socrates continued to be felt in the field of ethics, the ethics of the Greeks were at best narrow and egotistical. What a light was poured upon all questions of morality by that one divine axiom, "Love your enemy." No Greek ever attained the sublimity of such a point of view. Still, the progress made by the Greeks was immense, and they must ever occupy in the history of humanity an honourable place.
_III.--Philosophy and Science_
Francis Bacon is the father of experimental philosophy. He owes his t.i.tle to his method. Many philosophers, ancient and modern, had cursorily referred to observation and experiment as furnishing the materials of physical knowledge; but no one before him had attempted to systematise the true method of discovery.
He begins his great work by examining into the permanent causes of error, as these were likely to be operative even after the reformation of science. For this reason he calls them idols, or false appearances (from the Greek, _eidolon_), and he divides them into four cla.s.ses: the idols of the tribe, or the causes of error due to the general defects of the human mind; the idols of the den, which spring from weaknesses peculiar to the character of the individual student; the idols of the forum, which arise out of the intercourse of society and the power that words sometimes have of governing thought; and, finally, the idols of the theatre, which men of great learning pursue when they follow the systems of famous but mistaken thinkers.
After this preliminary discussion, Bacon goes on to describe the methods of inductive science. The first step consists in preparing a history of the phenomena to be explained in all their modifications and varieties.
This history must include not merely such facts as spontaneously offer themselves, but all experiments inst.i.tuted for the sake of discovery. It must be composed with great care; the facts should be accurately related and distinctly arranged, and their authenticity diligently examined; those that rest on doubtful evidence should not be rejected, but noted as uncertain, with the grounds of the judgment so formed. This last part of the method, says Bacon, is very necessary, for facts often appear incredible only because we are ill-informed, and they cease to seem marvellous when our knowledge is further extended.
When this record of facts, this "natural history," is completed, an attempt may then be made to discover, by a comparison of the various facts, the cause of the phenomena. Here it is of the utmost importance to bear in mind that all facts have not the same value. There are, as Bacon points out, twenty-seven species of facts, and he concludes that in any science where facts cannot be tested by experiment there can be no conclusive evidence.
Thus it will be seen that Bacon"s method was a system of specific rules.
He did not merely tell men to make observations and experiments; he taught them how observations and experiments ought to be made.
As Bacon was the father of modern science, so Rene Descartes was the father of modern philosophy. Born in 1596, and perplexed by the movement of scepticism produced by the Renaissance, the French thinker endeavoured to find some ground of certainty in the fact that he at least knew of his own existence. Hence his famous saying: _Cogito, ergo sum_--"I think, therefore I exist." Consciousness, said he, is the basis of all knowledge. The process then is simple: examine your consciousness, and its clear replies will be science. Hence the vital portion of his system lies in this axiom: "All clear ideas are true."
The fallacy in his system can be briefly exposed. Consciousness is, no doubt, the ultimate ground of certainty of existence for _me_. But though I am conscious of all that pa.s.ses within myself, I am not conscious of what pa.s.ses in anything not myself. All that I can possibly know of anything not myself lies in its effects upon me. Any other ideas I may have in regard to the outside world are founded only on inferences, and directly I leave the ground of consciousness for the region of inference my knowledge becomes questionable.
It was this defect in Cartesianism which Baruch Spinoza, the great Jewish thinker of Amsterdam, set out to rectify. Spinoza asked himself: What was the reality which lies beneath all appearance? We see everywhere transformations perishable and perishing, yet there must be something beneath which is imperishable and immutable. What is it? In Spinoza"s view, the absolute existence is G.o.d. All that exists, exists in and by G.o.d. Taking the words of St. Paul, "In Him we live and move and have our being," as his motto, he undertook to trace the relations of the world to G.o.d and to man, and those of man to society.
To John Locke, born at Wrington, in Somerset, in 1632, the problem presented itself in another way. Instead of accepting the validity of clear ideas, as Descartes and Spinoza did, he adopted the Baconian method, and opened the inquiry into the origin and formation of ideas.
Separating himself from the philosophers who held that the mind was capable of arriving at knowledge independent of experience, and from the sceptics who maintained that the senses were the only channels of information, he showed that ideas were derived from two sources--sensation and reflection.
He was succeeded by George Berkeley, Bishop of Cloyne, born at Kilcrin in Kilkenny, in 1684. He defeated the sceptics on their own ground.
There is nothing in the world, he says, except our own sensations and ideas. In order to exist for us, things have to be perceived by the mind; therefore, everything, in order to exist, must exist in the mind of G.o.d. But when Berkeley had proved that matter was figment, David Hume, born in 1711, came forward and showed that mind was also an illusion. You know nothing of matter, said Berkeley; you have only perceptions and the ideas based thereon. You know nothing of mind, replied Hume; you have only a succession of sensations and ideas.
Against Hume rose up in Germany a famous school of philosophers beginning with Immanuel Kant, who was born in Prussia in 1724. Kant attempted to prove that the human reason was not untrustworthy, as Hume a.s.sumed, but limited, and that, within certain bounds, it was capable of arriving at practical truths. Kant"s disciples, however, were not content with this modest restatement. Taking it too readily for granted that Hume"s objections had been overcome, they proceeded to revive that unbounded faith in mere speculation which had been the distemper of the Greek mind. Fichte and Sch.e.l.ling were the first thinkers of note to attempt again to solve by logic the mystery of the universe.
But their works are now obscured by the achievement of Hegel, who began to teach at Berlin in 1818. Hegel holds that the real universe is a universe of ideas to which his philosophy is the key, but, as ideas realise themselves in s.p.a.ce and time, they come within the scope of the man of science. It is said that all bad German systems of philosophy when they die come to England. Hegelianism has certainly been very fashionable in this country, and its influence is still observable in academic circles.
Auguste Comte is the Bacon of the nineteenth century. It has been his object to construct a _positive_ philosophy; that is to say, a doctrine capable of embracing all the sciences, and, with them, all the problems of social life. He holds that every branch of knowledge pa.s.ses through three stages: the supernatural, or fict.i.tious; the metaphysical or abstract; the positive or scientific. When the positive method is adopted, then shall we again have one general doctrine, powerful because general.
The metaphysicians have failed to penetrate to the causes of things, but the men of science are succeeding in the humbler but far more useful work of tracing some of the laws that govern the phenomena of nature, and foreseeing their operations. It is only where the philosophers started matters capable of _positive_ treatment that any advance has been made in metaphysics. For the rest, philosophy leaves us in the nineteenth century at precisely the same point at which we were in the fifth. Thus is the circle completed.
JOHN LOCKE
Concerning the Human Understanding
John Locke was born at Wrington, Somersetshire, England, Aug. 29, 1632. He was educated at Westminster and at Christ Church, Oxford; but his temperament rebelled against the system of education still in vogue and the public disputations of the schools, which he thought "invented for wrangling and ostentation rather than to discover truth." It was his study of Descartes that first "gave him a relish of philosophical things." From 1683 to 1689 he found it prudent to sojourn in Holland. In the latter year he returned to England, bringing with him the ma.n.u.script of the "Essay Concerning Human Understanding," which appeared in the spring of 1690. Few works of philosophy have made their way more rapidly than the "Essay." Twenty editions appeared before 1700. The design of the book, Locke explains in the introduction, is to inquire "into the origin, certainty, and extent of human knowledge, together with the grounds and degrees of belief, opinion, and a.s.sent." Locke died on October 28, 1704.
_I.--The Nature of Simple Ideas_
"Idea" being that term which, I think, serves best to stand for whatsoever is the object of the understanding. I have used it to express whatever is meant by phantasm, notion, species, or whatever it is the mind can be employed about in thinking. Let us, then, suppose the mind to be, as we say, white paper void of all characters--without any ideas.
Whence comes it by that vast store which the busy and boundless fancy of man has painted on it with an almost endless variety? To this, I answer in one word--Experience; in that all our knowledge is founded, and from that it ultimately derives itself.
Let anyone examine his own thoughts and thoroughly search his understanding, and then let him tell me whether of all the original ideas he has there are any other than of the objects of his senses, or of the observations of his mind considered as objects of his reflection. Though the qualities that affect our senses are, in the things themselves, so united and blended that there is no separation, no distance between them, yet it is plain the ideas they produce in the mind enter by the senses simple and unmixed. For, though the sight and touch often take in from the same object at the same time different ideas, yet the simple ideas thus united in the same subject are as perfectly distinct as those that come in by different senses; the coldness and hardness which a man feels in a piece of ice being as distinct ideas in the mind as the smell and whiteness of a lily, and each of them being in itself uncompounded, contains nothing but one uniform appearance, or conception, in the mind, and is not distinguishable into different ideas.
When the understanding is once stored with these simple ideas, it has the power to repeat, compare, and unite them even to an almost infinite variety, and so can make at will new complex ideas. But it is not in the power of any most exalted wit or enlarged understanding, by any quickness or variety of thought, to invent or frame one new simple idea in the mind, nor to destroy those that are there. I would have anyone try to fancy any taste which had never affected his palate, or frame the idea of a scent he had never smelt; and when he can do this, I will also conclude that a blind man hath ideas of colours and a deaf man true, distinct notions of sound.
There are some ideas which have admittance only through one sense which is peculiarly adapted to receive them. Thus, light and colours come in only by the eye, all kinds of noises by the ear, the tastes and smells by the nose and palate. The most considerable of those belonging to the touch are heat, cold, and solidity--which is the idea that belongs to the body, whereby we conceive it to fill s.p.a.ce.
Simple ideas of divers senses are the ideas of s.p.a.ce or extension, figure, rest, and motion, for these make perceivable impressions both on the eyes and touch, and we can receive and convey into our minds the ideas of the extension, figure, motion, and rest of bodies both by seeing and feeling.
The mind, receiving the ideas mentioned in the foregoing from without, when it turns its view inward upon itself and observes its own actions about those ideas it has, takes from thence other ideas which are as capable to be the objects of its contemplation as any of those it received from foreign things. The two great and princ.i.p.al actions of the mind which are most frequently considered, and which are so frequent that everyone that pleases may take notice of them in himself, are these two--Perception or Thinking, and Volition or Will. The power of thinking is called the Understanding, and the power of volition is called the Will. And these two powers, or abilities, in the mind are denominated Faculties. Some of the modes of these simple ideas of reflection are remembrance, discerning, reasoning, judging, knowledge, faith.
It has, further, pleased our wise Creator to annex to several objects and to the ideas which we receive from them, as also to several of our thoughts, a concomitant pleasure, and that in several objects to several degrees, that those faculties which He has endowed us with might not remain wholly idle and unemployed by us. Pain has the same efficacy and use to set us on work that pleasure has, we being as ready to employ our faculties to avoid that as to pursue this.
Existence and unity are two other ideas that are suggested to the understanding by every object without and every idea within. Power, also, is another of those simple ideas which we receive from sensation and reflection; and, besides these, there is succession.
Nor let anyone think these too narrow bounds for the capacious mind of man to expatiate in, which takes its flight farther than the stars and cannot be confined by the limits of the world, that extends its thoughts often even beyond the utmost expansion of matter and makes excursions into that incomprehensible inane. Nor will it be so strange to think these few simple ideas sufficient to employ the quickest thought or largest capacity if we consider how many words may be made out of the various composition of twenty-four letters; or if, going one step farther, we will but reflect on the variety of combinations that may be made with barely one of the above-mentioned ideas, _viz._, number, whose stock is inexhaustible. And what a large and immense field doth extension alone afford the mathematicians!
_II.--Of Idea-Producing Qualities_
The power to produce any idea in our mind I call Quality of the subject wherein that power is. Qualities are, first, such as are utterly inseparable from the body in what state soever it be. These I call original or primary qualities, which I think we may observe to produce simple ideas in us, _viz._, solidity, extension, figure, motion or rest, and number.
Secondly, such qualities which in truth are nothing in the objects themselves, but powers to produce various sensations in us by their primary qualities, _i.e._, by the bulk, figure, texture, and motion of their insensible parts. These secondary qualities are colours, sounds, tastes, etc. From whence I think it is easy to draw this observation: that the ideas of primary qualities of bodies are resemblances of them, but the ideas produced in us by the secondary qualities have no resemblance in them at all.
If anyone will consider that the same fire that at one distance produces in us the sensation of warmth does, at a nearer approach, produce in us the far different sensation of pain, let him bethink himself what reason he has to say that his idea of warmth, which was produced in him by fire, is actually in the fire; and his idea of pain which the same fire produced in him in the same way, is not in the fire. The particular bulk, number, figure, and motion of the parts of fire or snow are really in them, whether anyone"s senses perceive them or not; and, therefore, they may be called real qualities, because they really exist in those bodies. But light, heat, whiteness, or coldness are no more really in them than sickness or pain is in manna. Take away the sensation of them; let not the eyes see light or colours, nor the ears hear sounds; let the palate not taste, nor the nose smell; and all colours, tastes, odours, and sounds, as they are such particular ideas, vanish and cease, and are reduced to their causes, _i.e._, bulk, figure, and motion of parts.
_III.--Various Faculties of the Mind_
What perception is everyone will know better by reflecting on what he does himself when he sees, hears, feels, etc., or thinks, than by any discourse of mine. This is certain, that whatever alterations are made in the body, if they reach not the mind, whatever impressions are made on the outward parts, if they are not taken notice of within, there is no perception.
We ought further to consider concerning perception, that the ideas we receive by sensation are often in grown people altered by the judgment without our taking any notice of it. When we set before our eyes a round globe of any uniform colour--_e.g._, gold, alabaster, or jet--it is certain that the idea thereby imprinted in our mind is of a flat circle variously shadowed with several degrees of light and brightness coming to our eyes. But we having by use been accustomed to perceive what kind of appearances convex bodies are wont to make in us, what alterations are made in the reflections of light by the difference of the sensible figures of bodies, the judgment presently, by an habitual custom, alters the appearances into their causes; so that from that which is truly a variety of shadow or colour collecting the figure, it makes it pa.s.s for a mark of figure, and frames to itself the perception of a convex figure and a uniform colour, when the idea we receive from thence is only a plane variously coloured, as is evident in painting. Perception, then, is the first operation of our intellectual faculties, and the inlet of all knowledge into our minds.
The next faculty of the mind whereby it makes a further progress towards knowledge is that which I call Retention, or the keeping of those simple ideas which from sensation or reflection it hath received. This is done, first, by keeping the idea which is brought into it for some time actually in view, which is called Contemplation. The other way of retention is the power to revive again in our minds those ideas which after imprinting have disappeared, or have been, as it were, laid aside out of sight; and thus we do when we conceive heat or light, yellow or sweet, the object being removed. This is memory, which is, as it were, the storehouse of our ideas.
Another faculty we may take notice of in our minds is that of Discerning, and distinguishing between the several ideas it has. It is not enough to have a confused perception of something in general. Unless the mind had a distinct perception of different objects and their qualities, it would be capable of very little knowledge, though the bodies that affect us were as busy about us as they are now, and the mind were continually employed in thinking. On this faculty of distinguishing one thing from another depends the evidence and certainty of several even very general propositions which have pa.s.sed for innate truths, because men, overlooking the true cause why those propositions find universal a.s.sent, impute it wholly to native uniform impressions; whereas it, in truth, depends upon this clear discerning faculty of the mind, whereby it perceives two ideas to be the same or different.
The comparing of ideas one with another is the operation of the mind upon which depends all that large tribe of ideas comprehended under relations. The next operation is composition, whereby the mind puts together several simple ideas and combines them into complex ones.