S. Austin Allibone, comp. Prose Quotations from Socrates to Macaulay. 1880.
Above all subjects study thine own self. For no knowledge that terminates in curiosity or speculation is comparable to that which is of use; and of all useful knowledge that is most so which consists in the due care and just notions of ourselves. This study is a debt which every one owes himself. Let us not then be so lavish, so unjust, as not to pay this debt, by spending some part at least, if we cannot all, or most of our time and care upon that which has the most indefeasible claim to it. Govern your passions, manage your actions with prudence, and where false steps have been made, correct them for the future. Let nothing he allowed to grow headstrong and disorderly; but bring all under discipline. Set all your faults before your eyes, and pass sentence upon yourself with the same severity as you would do upon another for whom no partiality had biassed your judgment.
Reader, you have been bred in a land abounding with men able in arts, learning, and knowledges manifold: this man in one, this in another; few in many, none in all. But there is one art of which every man should be a master,the art of reflection. If you are not a thinking man, to what purpose are you a man at all? In like manner, there is one knowledge which it is every mans duty and interest to acquire, namely, self-knowledge. Or to what end was man alone, of all animals, endued by the Creator with the faculty of self-consciousness?
The imperfection of self-knowledge must often expose us to the danger of self-delusion, the only remedy for which is self-distrust: this evinces the necessity of self-denial; and our general security (with divine assistance) must be in self-command.
Though this vicinity of ourselves to ourselves cannot give us the full prospect of all the intrigues of our nature, yet we have much more advantage to know ourselves than to know other things without us.
When a man employs himself upon remote and unnecessary subjects, and wastes his life upon questions which cannot be resolved, and of which the solution would conduce very little to the advancement of happiness; when he lavishes his hours in calculating the weight of the terraqueous globe, or in adjusting successive systems of worlds beyond the reach of the telescope; he may be very properly recalled from his excursions by this precept, and reminded that there is a nearer being with which it is his duty to be more acquainted; and from which his attention has hitherto been withheld by studies to which he has no other motive than vanity or curiosity.
It is by the consciousness it has of its present thoughts and actions, that it is self to itself now, and so will be the same self as far as the same consciousness can extend to actions past or to come.
We find this great precept often repeated in Plato, do thine own work, and know thyself. Of which two parts both the one and the other generally comprehend our whole duty, and consequently do each of them complicate and involve the other; for who will do his own work aright will find that his first lesson is to know himself: and who rightly understands himself will never mistake another mans work for his own, but will love and improve himself above all other things, will refuse superfluous employments, and reject all unprofitable thoughts and propositions.
Michel de Montaigne: Essays, Cottons 3d ed., ch. iii.
If self-knowledge be a path to virtue, virtue is a much better one to self-knowledge. The more pure the soul becomes, it will, like precious stones that are sensible to the contact of poison, shrink from the fetid vapours of evil impressions.
Of all literary exercitations, whether designed for the use or entertainment of the world, there are none of so much importance, or so immediately our concern, as those which let us into the knowledge of our own nature. Others may exercise the understanding or amuse the imagination; but these only can improve the heart and form the human mind to wisdom.