For those who are unable, Herodotus, to work in detail through all that I have written about nature, or to peruse the larger books which I have composed, I have already prepared at sufficient length an epitome of the whole system, that they may keep adequately in mind at least the most general principles in each department, in order that as occasion arises they may be able to assist themselves on the most important points, in so far as they undertake the study of nature.  But those also who have made considerable progress in the survey of the main principles ought to bear in mind the scheme of the whole system set forth in its essentials.  For we have frequent need of the general view, but not so often of the detailed exposition.

Indeed it is necessary to go back on the main principles, and constantly to fix in one's memory enough to give one the most essential comprehension of the truth.  And in fact the accurate knowledge of details will be fully discovered, if the general principles in the various departments are thoroughly grasped and borne in mind; for even in the case of one fully initiated the most essential feature in all accurate knowledge is the capacity to make a rapid use of observation and mental apprehension, and this can be done if everything is summed up in elementary principles and formulae.  For it is not possible for any one to abbreviate the complete course through the whole system, if he cannot embrace in his own mind by means of short formulae all that might be set out with accuracy in detail.  Wherefore since the method I have described is valuable to all those who are accustomed to the investigation of nature, I who urge upon others the constant occupation in the investigation of nature, and find my own peace chiefly in a life so occupied, have composed for you another epitome on these lines, summing up the first principles of the whole doctrine.

First of all, Herodotus, we must grasp the ideas attached to words, in order that we may be able to refer to them and so to judge the inferences of opinion or problems of investigation or reflection, so that we may not either leave everything uncertain and go on explaining to infinity or use words devoid of meaning.  For this purpose it is essential that the first mental image associated with each word should be regarded, and that there should be no need of explanation, if we are really to have a standard to which to refer a problem of investigation or reflection or a mental inference.  And besides we must keep all our investigations in accord with our sensations, and in particular with the immediate apprehensions whether of the mind or of any one of the instruments of judgment, and likewise in accord with the feelings existing in us, in order that we may have indications whereby we may judge both the problem of sense-perception and the unseen.

Having made these points clear, we must now consider things imperceptible to the senses.  First of all, that nothing is created out of that which does not exist: for if it were, everything would be created out of everything with no need of seeds.  And again, if that which disappears were destroyed into that which did not exist, all things would have perished, since that into which they were dissolved would not exist.

Furthermore, the universe always was such as it is now, and always will be the same.  For there is nothing into which it changes: for outside the universe there is nothing which could come into it and bring about the change.

Moreover, the universe is bodies and space: for that bodies exist, sense itself witnesses in the experience of all men, and in accordance with the evidence of sense we must of necessity judge of the imperceptible by reasoning, as I have already said.  And if there were not that which we term void and place and intangible existence, bodies would have nowhere to exist and nothing through which to move, as they are seen to move.

And besides these two nothing can even be thought of either by conception or on the analogy of things conceivable such as could be grasped as whole existences and not spoken of as the accidents or properties of such existences.  Furthermore, among bodies some are compounds, and others those of which compounds are formed.  And these latter are indivisible and unalterable (if, that is, all things are not to be destroyed into the non-existent, but something permanent is to remain behind at the dissolution of compounds): they are completely solid in nature, and can by no means be dissolved in any part.  So it must needs be that the first-beginnings are indivisible corporeal existences.

Moreover, the universe is boundless.  For that which is bounded has an extreme point: and the extreme point is seen against something else.  So that as it has no extreme point, it has no limit; and as it has no limit, it must be boundless and not bounded.  Furthermore, the infinite is boundless both in the number of the bodies and in the extent of the void.  For if on the one hand the void were boundless, and the bodies limited in number, the bodies could not stay anywhere, but would be carried about and scattered through the infinite void, not having other bodies to support them and keep them in place by means of collisions.  But if, on the other hand, the void were limited, the infinite bodies would not have room wherein to take their place.

Besides this the indivisible and solid bodies, out of which too the compounds are created and into which they are dissolved, have an incomprehensible number of varieties in shape: for it is not possible that such great varieties of things should arise from the same atomic shapes, if they are limited in number.  And so in each shape the atoms are quite infinite in number, but their differences of shape are not quite infinite, but only incomprehensible in number.

And the atoms move continuously for all time, some of them falling straight down, others swerving, and others recoiling from their collisions.  And of the latter, some are borne on, separating to a long distance from one another, while others again recoil and recoil, whenever they chance to be checked by the interlacing with others, or else shut in by atoms interlaced around them.  For on the one hand the nature of the void which separates each atom by itself brings this about, as it is not able to afford resistance, and on the other hand the hardness which belongs to the atoms makes them recoil after collision to as great a distance as the interlacing permits separation after the collision.  And these motions have no beginning, since the atoms and the void are the cause.

These brief sayings, if all these points are borne in mind, afford a sufficient outline for our understanding of the nature of existing things.

Furthermore, there are infinite worlds both like and unlike this world of ours.  For the atoms being infinite in number, as was proved already, are borne on far out into space.  For those atoms, which are of such nature that a world could be created out of them or made by them, have not been used up either on one world or on a limited number of worlds, nor again on all the worlds which are alike, or on those which are different from these.  So that there nowhere exists an obstacle to the infinite number of the worlds.

Moreover, there are images like in shape to the solid bodies, far surpassing perceptible things in their subtlety of texture.  For it is not impossible that such emanations should be formed in that which surrounds the objects, nor that there should be opportunities for the formation of such hollow and thin frames, nor that there should be effluences which preserve the respective position and order which they had before in the solid bodies: these images we call idols.

Next, nothing among perceptible things contradicts the belief that the images have unsurpassable fineness of texture.  And for this reason they have also unsurpassable speed of motion, since the movement of all their atoms is uniform, and besides nothing or very few things hinder their emission by collisions, whereas a body composed of many or infinite atoms is at once hindered by collisions.

Besides this, nothing contradicts the belief that the creation of the idols takes place as quick as thought.  For the flow of atoms from the surface of bodies is continuous, yet it cannot be detected by any lessening in the size of the object because of the constant filling up of what is lost.  The flow of images preserves for a long time the position and order of the atoms in the solid body, though it is occasionally confused.  Moreover, compound idols are quickly formed in the air around, because it is not necessary for their substance to be filled in deep inside: and besides there are certain other methods in which existences of this sort are produced.  For not one of these beliefs is contradicted by our sensations, if one looks to see in what way sensation will bring us the clear visions from external objects, and in what way again the corresponding sequences of qualities and movements.

Now we must suppose too that it is when something enters us from external objects that we not only see but think of their shapes.  For external objects could not make on us an impression of the nature of their own color and shape by means of the air which lies between us and them, nor again by means of the rays or effluences of any sort which pass from us to them - nearly so well as if models, similar in color and shape, leave the objects and enter according to their respective size either into our sight or into our mind; moving along swiftly, and so by this means reproducing the image of a single continuous thing and preserving the corresponding sequence of qualities and movements from the original object as the result of their uniform contact with us, kept up by the vibration of the atoms deep in the interior of the concrete body.

And every image which we obtain by an act of apprehension on the part of the mind or of the sense-organs, whether of shape or of properties, this image is the shape or the properties of the concrete object, and is produced by the constant repetition of the image or the impression it has left.  Now falsehood and error always lie in the addition of opinion with regard to what is waiting to be confirmed or not contradicted, and then is not confirmed or is contradicted.

For the similarity between the things which exist, which we call real and the images received as a likeness of things and produced either in sleep or through some other acts of apprehension on the part of the mind or the other instruments of judgment, could never be, unless there were some effluences of this nature actually brought into contact with our senses.  And error would not exist unless another kind of movement too were produced inside ourselves, closely linked to the apprehension of images, but differing from it; and it is owing to this, supposing it is not confirmed, or is contradicted, that falsehood arises; but if it is confirmed or not contradicted, it is true.  Therefore we must do our best to keep this doctrine in mind, in order that on the one hand the standards of judgment dependent on the clear visions may not be undermined, and on the other error may not be as firmly established as truth and so throw all into confusion.

Moreover, hearing, too, results when a current is carried off from the object speaking or sounding or making a noise, or causing in any other way a sensation of hearing.  Now this current is split up into particles, each like the whole, which at the same time preserve a correspondence of qualities with one another and a unity of character which stretches right back to the object which emitted the sound: this unity it is which in most cases produces comprehension in the recipient, or, if not, merely makes manifest the presence of the external object.

For without the transference from the object of some correspondence of qualities, comprehension of this nature could not result.  We must not then suppose that the actual air is molded into shape by the voice which is emitted or by other similar sounds - for it will be very far from being so acted upon by it - but that the blow which takes place inside us, when we emit our voice, causes at once a squeezing out of certain particles, which produce a stream of breath, of such a character as to afford us the sensation of hearing.

Furthermore, we must suppose that smell too, just like hearing, could never bring about any sensation, unless there were certain particles carried off from the object of suitable size to stir this sense-organ, some of them in a manner disorderly and alien to it, others in a regular manner and akin in nature.

Moreover, we must suppose that the atoms do not possess any of the qualities belonging to perceptible things, except shape, weight, and size, and all that necessarily goes with shape.  For every quality changes; but the atoms do not change at all, since there must needs be something which remains solid and indissoluble at the dissolution of compounds, which can cause changes; not changes into the non-existent or from the non-existent, but changes effected by the shifting of position of some particles, and by the addition or departure of others.

For this reason it is essential that the bodies which shift their position should be imperishable and should not possess the nature of what changes, but parts and configuration of their own.  For thus much must needs remain constant.  For even in things perceptible to us which change their shape by the withdrawal of matter it is seen that shape remains to them, whereas the qualities do not remain in the changing object, in the way in which shape is left behind, but are lost from the entire body.  Now these particles which are left behind are sufficient to cause the differences in compound bodies, since it is essential that some things should be left behind and not be destroyed into the non-existent.

Moreover, we must not either suppose that every size exists among the atoms, in order that the evidence of phenomena may not contradict us, but we must suppose that there are some variations of size.  For if this be the case, we can give a better account of what occurs in our feelings and sensations.  But the existence of atoms of every size is not required to explain the differences of qualities in things, and at the same time some atoms would be bound to come within our ken and be visible; but this is never seen to be the case, nor is it possible to imagine how an atom could become visible.

Besides this we must not suppose that in a limited body there can be infinite parts or parts of every degree of smallness.  Therefore,  we must not only do away with division into smaller and smaller parts to infinity, in order that we may not make all things weak, and so in the composition of aggregate bodies be compelled to crush and squander the things that exist into the non-existent, but we must not either suppose that in limited bodies there is a possibility of continuing to infinity in passing ever to smaller and smaller parts.  For if once one says that there are infinite parts in a body or parts of any degree of smallness, it is not possible to conceive how this should be, and indeed how could the body any longer be limited in size?  (For it is obvious that these infinite particles must be of some size or other; and however small they may be, the size of the body too would be infinite.)

And again, since the limited body has an extreme point, which is distinguishable, even though not perceptible by itself, you cannot conceive that the succeeding point to it is not similar in character, or that if you go on in this way from one point to another, it should be possible for you to proceed to infinity marking such points in your mind.

We must notice also that the least thing in sensation is neither exactly like that which admits of progression from one part to another, nor again is it in every respect wholly unlike it, but it has a certain affinity with such bodies, yet cannot be divided into parts.  But when on the analogy of this resemblance we think to divide off parts of it, one on the one side and another on the other, it must needs be that another point like the first meets our view.  And we look at these points in succession starting from the first, not within the limits of the same point nor in contact part with part, but yet by means of their own proper characteristics measuring the size of bodies, more in a greater body and fewer in a smaller.

Now we must suppose that the least part in the atom too bears the same relation to the whole; for though in smallness it is obvious that it exceeds that which is seen by sensation, yet it has the same relation to sensible bodies that the atom has size, only we placed it far below them in smallness.  Further we must consider these least indivisible points as boundary-marks, providing in themselves as primary units the measure of size for the atoms, both for the smaller and the greater, in our contemplation of these unseen bodies by means of thought.  For the affinity which the least parts of the atom have to the homogeneous parts of sensible things is sufficient to justify our conclusion to this extent: but that they should ever come together as bodies with motion is quite impossible.

Furthermore, in the infinite we must not speak of 'up' or 'down,' as though with reference to an absolute highest or lowest - and indeed we must say that, though it is possible to proceed to infinity in the direction above our heads from wherever we take our stand, the absolute highest point will never appear to us - nor yet can that which passes beneath the point thought of to infinity be at the same time both up and down in reference to the same thing: for it is impossible to think this.  So that it is possible to consider as one single motion that which is thought of as the upward motion to infinity and as another the downward motion, even though that which passes from us into the regions above our heads arrives countless times at the feet of beings above and that which passes downwards from us at the head of beings below; for none the less the whole motions are thought of as opposed, the one to the other, to infinity.

Moreover, the atoms must move with equal speed, when they are borne onwards through the void, nothing colliding with them.  For neither will the heavy move more quickly than the small and light, when, that is, nothing meets them: nor again the small more quickly than the great, having their whole course uniform, when nothing collides with them either: nor is the motion upwards or sideways owing to blows quicker, nor again that downwards owing to their own weight.  For as long as either of the two motions prevails, so long will it have a course as quick as thought, until something checks it either from outside or from its own weight counteracting the force of that which dealt the blow.

Moreover, their passage through the void, when it takes place without meeting any bodies which might collide, accomplishes every comprehensible distance in an inconceivably short time.  For it is collision and its absence which take the outward appearance of slowness and quickness.  Moreover, it will be said that in compound bodies too one atom is faster than another, though as a matter of fact all are equal in speed: this will be said because even in the least period of continuous time all the atoms in aggregate bodies move towards one place, even though in moments of time perceptible only by thought they do not move towards one place but are constantly jostling one against another, until the continuity of their movement comes under the ken of sensation.

For the addition of opinion with regard to the unseen, that the moments perceptible only by thought will also contain continuity of motion, is not true in such cases; for we must remember that it is what we observe with the senses or grasp with the mind by an apprehension
that is true.  Nor must it either be supposed that in moments perceptible only by thought the moving body too passes to the several places to which its component atoms move (for this too is unthinkable, and in that case, when it arrives all together in a sensible period of time from any point that may be in the infinite void, it would not be taking its departure from the place from which we apprehend its motion); for the motion of the whole body will be the outward expression of its internal collisions, even though up to the limits of perception we suppose the speed of its motion not to be retarded by collision.  It is of advantage to grasp this first principle as well.

Next, referring always to the sensations and the feelings, for in this way you will obtain the most trustworthy ground of belief, you must consider that the soul is a body of fine particles distributed throughout the whole structure, and most resembling wind with a certain admixture of heat, and in some respects like to one of these and in some to the other.  There is also the part which is many degrees more advanced even than these in fineness of composition, and for this reason is more capable of feeling in harmony with the rest of the structure as well.  Now all this is made manifest by the activities of the soul and the feelings and the readiness of its movements and its processes of thought and by what we lose at the moment of death.

Further, you must grasp that the soul possesses the chief cause of sensation: yet it could not have acquired sensation, unless it were in some way enclosed by the rest of the structure.  And this in its turn having afforded the soul this cause of sensation acquires itself too a share in this contingent capacity from the soul.  Yet it does not acquire all the capacities which the soul possesses: and therefore when the soul is released from the body, the body no longer has sensation.

For it never possessed this power in itself, but used to afford opportunity for it to another existence, brought into being at the same time with itself: and this existence, owing to the power now consummated within itself as a result of motion, used spontaneously to produce for itself the capacity of sensation and then to communicate it to the body as well, in virtue of its contact and correspondence of movement, as I have already said.  Therefore, so long as the soul remains in the body, even though some other part of the body be lost, it will never lose sensation; nay more, whatever portions of the soul may perish too, when that which enclosed it is removed either in whole or in part, if the soul continues to exist at all, it will retain sensation.

On the other hand the rest of the structure, though it continues to exist either as a whole or in part, does not retain sensation, if it has once lost that sum of atoms, however small it be, which together goes to produce the nature of the soul.  Moreover, if the whole structure is dissolved, the soul is dispersed and no longer has the same powers nor performs its movements, so that it does not possess sensation either.  For it is impossible to imagine it with sensation, if it is not in this organism and cannot effect these movements, when what encloses and surrounds it is no longer the same as the surroundings in which it now exists and performs these movements.

Furthermore, we must clearly comprehend as well, that the incorporeal in the general acceptation of the term is applied to that which could be thought of as such as an independent existence.  Now it is impossible to conceive the incorporeal as a separate existence, except the void: and the void can neither act nor be acted upon, but only provides opportunity of motion through itself to bodies.  So that those who say that the soul is incorporeal are talking idly.  For it would not be able to act or be acted on in any respect, if it were of this nature.  But as it is, both these occurrences are clearly distinguished in respect of the soul.  Now if one refers all these reasonings about the soul to the standards of feeling and sensation and remembers what was said at the outset, he will see that they are sufficiently embraced in these general formulae to enable him to work out with certainty on this basis the details of the system as well.

Moreover, as regards shape and color and size and weight and all other things that are predicated of body, as though they were concomitant properties either of all things or of things visible or recognizable through the sensation of these qualities, we must not suppose that they are either independent existences (for it is impossible to imagine that), nor that they absolutely do not exist, nor that they are some other kind of incorporeal existence accompanying body, nor that they are material parts of body: rather we should suppose that the whole body in its totality owes its own permanent existence to all these, yet not in the sense that it is composed of properties brought together to form it (as when, for instance, a larger structure is put together out of the parts which compose it, whether the first units of size or other parts smaller than itself, whatever it is), but only, as I say, that it owes its own permanent existence to all of them.

All these properties have their own peculiar means of being perceived and distinguished, provided always that the aggregate body goes along with them and is never wrested from them, but in virtue of its comprehension as an aggregate of qualities acquires the predicate of body.

Furthermore, there often happen to bodies and yet do not permanently accompany them accidents, of which we must suppose neither that they do not exist at all nor that they have the nature of a whole body, nor that they can be classed among unseen things nor as incorporeal.   So that when according to the most general usage we employ this name, we make it clear that accidents have neither the nature of the whole, which we comprehend in its aggregate and call body, nor that of the qualities which permanently accompany it, without which a given body cannot be conceived.

But as the result of certain acts of apprehension, provided the aggregate body goes along with them, they might each be given this name, but only on occasions when each one of them is seen to occur, since accidents are not permanent accompaniments.  And we must not banish this clear vision from the realm of existence, because it does not possess the nature of the whole to which it is joined nor that of the permanent accompaniments, nor must we suppose that such contingencies exist independently (for this is inconceivable both with regard to them and to the permanent properties), but, just as it appears in sensation, we must think of them all as accidents occurring to bodies, and that not as permanent accompaniments, or again as having in themselves a place in the ranks of material existence; rather they are seen to be just what our actual sensation shows their proper character to be.

Moreover, you must firmly grasp this point as well; we must not look for time, as we do for all other things which we look for in an object, by referring them to the general conceptions which we perceive in our own minds, but we must take the direct intuition, in accordance with which we speak of 'a long time' or 'a short time,' and examine it, applying our intuition to time as we do to other things.  Neither must we search for expressions as likely to be better, but employ just those which are in common use about it.

Nor again must we predicate of time anything else as having the same essential nature as this special perception, as some people do, but we must turn our thoughts particularly to that only with which we associate this peculiar perception and by which we measure it.  For indeed this requires no demonstration, but only reflection, to show that it is with days and nights and their divisions that we associate it, and likewise also with internal feelings or absence of feeling, and with movements and states of rest; in connection with these last again we think of this very perception as a peculiar kind of accident, and in virtue of this we call it time.

And in addition to what we have already said we must believe that worlds, and indeed every limited compound body which continuously exhibits a similar appearance to the things we see, were created from the infinite, and that all such things, greater and less alike, were separated off from individual agglomerations of matter; and that all are again dissolved, some more quickly, some more slowly, some suffering from one set of causes, others from another.  And further we must believe that these worlds were neither created all of necessity with one configuration nor yet with every kind of shape.

Furthermore, we must believe that in all worlds there are living creatures and plants and other things we see in this world; for indeed no one could prove that in a world of one kind there might or might not have been included the kinds of seeds from which living things and plants and all the rest of the things we see are composed, and that in a world of another kind they could not have been.

Moreover, we must suppose that human nature too was taught and constrained to do many things of every kind merely by circumstances, and that later on reasoning elaborated what had been suggested by nature and made further inventions, in some matters quickly, in others slowly, at some epochs and times making great advances, and lesser again at others.  And so names too were not at first deliberately given to things, but men's natures according to their different nationalities had their own peculiar feelings and received their peculiar impressions, and so each in their own way emitted air formed into shape by each of these feelings and impressions, according to the differences made in the different nations by the places of their abode as well.

And then later on by common consent in each nationality special names were deliberately given in order to make their meanings less ambiguous to one another and more briefly demonstrated.  And sometimes those who were acquainted with them brought in things hitherto unknown and introduced sounds for them, on some occasions being naturally constrained to utter them, and on others choosing them by reasoning in accordance with the prevailing mode of formation, and thus making their meaning clear.

Furthermore, the motions of the heavenly bodies and their turnings and eclipses and risings and settings, and kindred phenomena to these, must not be thought to be due to any being who controls and ordains or has ordained them and at the same time enjoys perfect bliss together with immortality (for trouble and care and anger and kindness are not consistent with a life of blessedness, but these things come to pass where there is weakness and fear and dependence on neighbors).  Nor again must we believe that they, which are but fire agglomerated in a mass, possess blessedness, and voluntarily take upon themselves these movements.

But we must preserve their full majestic significance in all expressions which we apply to such conceptions, in order that there may not arise out of them opinions contrary to this notion of majesty.  Otherwise this very contradiction will cause the greatest disturbance in men's souls.  Therefore we must believe that it is due to the original inclusion of matter in such agglomerations during the birth-process of the world that this law of regular succession is also brought about.

Furthermore, we must believe that to discover accurately the cause of the most essential facts is the function of the science of nature, and that blessedness for us in the knowledge of celestial phenomena lies in this and in the understanding of the nature of the existences seen in these celestial phenomena, and of all else that is akin to the exact knowledge requisite for our happiness: in knowing too that what occurs in several ways or is capable of being otherwise has no place here, but that nothing which suggests doubt or alarm can be included at all in that which is naturally immortal and blessed.  Now this we can ascertain by our mind is absolutely the case.

But what falls within the investigation of risings and settings and turnings and eclipses, and all that is akin to this, is no longer of any value for the happiness which knowledge brings, but persons who have perceived all this, but yet do not know what are the natures of these things and what are the essential causes, are still in fear, just as if they did not know these things at all: indeed, their fear may be even greater, since the wonder which arises out of the observation of these things cannot discover any solution or realize the regulation of the essentials.

And for this very reason, even if we discover several causes for turnings and settings and risings and eclipses and the like, as has been the case already in our investigation of detail, we must not suppose that our inquiry into these things has not reached sufficient accuracy to contribute to our peace of mind and happiness.  So we must carefully consider in how many ways a similar phenomenon is produced on earth, when we reason about the causes of celestial phenomena and all that is imperceptible to the senses; and we must despise those persons who do not recognize either what exists or comes into being in one way only, or that which may occur in several ways in the case of things which can only be seen by use from a distance, and further are not aware under what conditions it is impossible to have peace of mind.  If, therefore, we think that a phenomenon probably occurs in some such particular way, and that in circumstances under which it is equally possible for us to be at peace, when we realize that it may occur in several ways, we shall be just as little disturbed as if we know that it occurs in some particular way.

And besides all these matters in general we must grasp this point, that the principal disturbance in the minds of men arises because they think that these celestial bodies are blessed and immortal, and yet have wills and actions and motives inconsistent, with these attributes; and because they are always expecting or imagining some everlasting misery, such as is depicted in legends, or even fear the loss of feeling in death as though it would concern them themselves; and, again, because they are brought to this pass not by reasoned opinion, but rather by some irrational presentiment, and therefore, as they do not know the limits of pain, they suffer a disturbance equally great or even more extensive than if they had reached this belief by opinion.  But peace of mind is being delivered from all this, and having a constant memory of the general and most essential principles.

Wherefore we must pay attention to internal feelings and to external sensations in general and in particular, according as the subject is general or particular, and to every immediate intuition in accordance with each of the standards of judgment.  For if we pay attention to these, we shall rightly trace the causes whence arose our mental disturbance and fear, and, by learning the true causes of celestial phenomena and all other occurrences that come to pass from time to time, we shall free ourselves from all which produces the utmost fear in other men.

Here, Herodotus, is my treatise on the chief points concerning the nature of the general principles, abridged so that my account would be easy to grasp with accuracy.  I think that, even if one were unable to proceed to all the detailed particulars of the system, he would from this obtain an unrivalled strength compared with other men.  For indeed he will clear up for himself many of the detailed points by reference to our general system, and these very principles, if he stores them in his mind, will constantly aid him.  For such is their character that even those who are at present engaged in working out the details to a considerable degree, or even completely, will be able to carry out the greater part of their investigations into the nature of the whole by conducting their analysis in reference to such a survey as this.  And as for all who are not fully among those on the way to being perfected, some of them can from this summary obtain a hasty view of the most important matters without oral instruction so as to secure peace of mind.