Principle

Every argument starts somewhere, and every action is undertaken for some reason that is not itself argued for at that moment. The idea of principle concerns these starting points. It includes the first truths from which demonstration proceeds, the axioms a geometer asks his reader to grant, the laws a physicist believes govern all of nature, the maxims a moralist treats as binding on every will, and the convictions a statesman or a private man keeps to when circumstances pull him another way. Marcus Aurelius says that reason proceeds from a first principle of its own¹. Channing speaks of principles that by nature rule over all knowledge and are all-comprehending and eternal². Pascal adds a note of humility: to understand the ultimate principles of being would be to know the Infinite³. Principle is a great idea for these books because nearly every author in them must decide what may be assumed and what must be proved. That decision shapes geometry, physics, ethics and politics alike.

The most rigorous treatment of the question in these volumes belongs to Pascal, writing on the geometrical mind. He observes that if we tried to define every term and prove every proposition, we would fall into an endless regress. Defining and proving must stop at primitive words and self-evident principles, which can be neither defined nor proved⁴. The geometer cannot prove his first principles, but the reason is not that they are obscure. They are so extremely obvious that there is nothing clearer to prove them by⁵. From this Pascal draws rules. One must omit no necessary principle, and one may demand as an axiom only what is perfectly evident^6,7. Proof works only when such axioms are proposed and remain uncontradicted⁸. A claim that is not evident in itself must be put forward as a principle or axiom and never slipped in as a definition⁹. Samuel Johnson, writing about something quite different, the making of a dictionary, reaches the same structure. As definition must end in words that cannot be defined, so nothing can be proved without supposing something known intuitively¹⁰. Yet Pascal in the *Thoughts* also warns that supposed ultimate premises are often not self-supporting at all and in fact rest on others¹¹. The regress stops in principle, but we may mistake where it stops.

So by what faculty are first principles known? Pascal’s answer is the famous one: the heart. We know first principles by the heart, and reason must trust them. The sceptics who try to dislodge them labour in vain¹². Principles are intuited and propositions inferred, both with certainty. Neither faculty may demand proofs of the other, since it would be absurd for reason to ask the heart to demonstrate its first principles before assenting to them¹³. Pascal joins this to his distinction between the geometrical and the intuitive mind. The geometer’s principles are plain but removed from ordinary use. The intuitive man’s principles are in common use but so numerous and fine that some escape notice, and error follows¹⁴. Intuitive principles are felt rather than seen and cannot be demonstrated in order¹⁵. For their part, intuitive men lack the patience to reach speculative first principles that lie far from common experience¹⁶.

Pascal does not rest easily in this answer, and his worry gives the sceptical challenge its sharpest form in these books. He asks whether the axioms common to all men conform to essential truth¹⁷. He notes that the mind and the will each have their own principles. Natural truths such as that the whole exceeds its part can compel belief, but so can maxims that are false¹⁸. The dogmatists’ strong point is that natural principles cannot sincerely be doubted. The sceptics reply that, not knowing our origin, we cannot tell whether we were made to grasp truth or falsehood^19,20. Pascal goes so far as to say that the principles of sceptics, Stoics and atheists are true, but their conclusions false, because the opposite principles are also true²¹. For Pascal the question of principles cannot be settled by philosophy alone.

Descartes takes the opposite path. He seeks a principle that doubt itself cannot touch, and finds it in I think, hence I am. He judges it so certain that the sceptics’ most extravagant suppositions cannot shake it, and accepts it without scruple as the first principle of his philosophy²². He holds to this principle when proving the existence of God and the soul, and accepts nothing that is not clearer than the demonstrations of the geometers²³. He then claims to find first principles innately in our minds and to deduce the most common effects of nature from them²⁴. His physical principles, he says, are so evident that understanding them suffices for assent²⁵. Hume cuts at the root of this. No original principle, he argues, has a prerogative above other self-evident ones that could ground the Cartesian doubt or justify building on it alone²⁶. Here the modern disagreement is plain. One side holds that a single indubitable principle can found the whole edifice of knowledge. The other holds that no principle enjoys such privilege.

The question of how principles are known leads to the question of how they are tested, and here the ancients set the pattern. In the *Phaedo* Socrates describes a method. Assume the principle that seems strongest and test whether its consequences agree. If pressed to defend the principle itself, assume a higher one, until some resting-place is reached²⁷. Even first principles that seem certain, he adds, should be carefully examined²⁸. In the *Crito* he keeps to principles he has long honoured unless better ones appear on the instant²⁹. Marcus Aurelius likewise counsels examining a matter from first principles³⁰.

The moderns turn this examination against inherited authority. Raleigh insists that philosophical principles are not undoubted merely because they are so called, or because masters have said them³¹. Copernicus judges that fixed principles would have spared the astronomers their errors³². Bacon demands that the putative principles and first notions of the sciences be tested before being accepted³³. Pascal observes that carrying custom back to its first principles destroys its authority³⁴, which is a warning as much as a method. In the arts, Goethe advises that maxims drawn from works of art be tested in practice, since agreement on fundamentals is rare³⁵. Hugo, by contrast, appeals confidently to immutable principles of composition³⁶, and Whitman pictures poets advancing through coverings and turmoils to first principles³⁷. Mill records that Stewart’s idea about the use of axioms in reasoning became the key that resolved a perplexity in his own logic³⁸.

Bacon gives the most influential modern account of how principles are discovered. His science, he says, seeks the invention of principles themselves rather than of things derived from principles³⁹. Axioms are to rise by degrees from particulars, so that the most general are reached last and are well defined⁴⁰. He rejects the hasty pursuit of practical results, because axioms rightly discovered will bring forth works in clusters⁴¹. Hume describes the same ascent. Abstract philosophers push inquiry from particulars to ever more general original principles⁴². Moralists and critics look for the principles behind varied sentiments, and one mental principle may be resolved into a more general one⁴³. Emerson gives the ascent a romantic turn. Discordant facts and opinions are reconciled as extremes of one principle, yet we never reach a final, highest principle, because every generalization is surpassed by a wider one⁴⁴. He also praises the great generalizations of Bacon, Berkeley, Swedenborg and Hegel as constants that circulate among thinkers, avenues into vast kingdoms of thought⁴⁵. Socrates looked for a resting-place at the top of the ascent. Emerson suspects there is none.

In natural science the principle appears as a universal law. George Long reports Zeno’s two original principles of all things, the acting and the acted upon⁴⁶. Helmholtz reaches his law by surveying many examples in order to recognise what is common to all forces⁴⁷. He finds that the capacity for work is exhausted as work is performed, while the total force is neither increased nor diminished⁴⁸. The universe’s store of force is thus unchanging, a general law comparable to the unalterability of mass⁴⁹. Huxley completes the picture from the side of application: applied science consists of deductions from general principles that have been established by reasoning and observation⁵⁰. Bacon’s inductive ascent and Descartes’ deductive descent here meet in one practice.

The moral question is whether conduct, like geometry, has a supreme principle. Socrates lays down as his first premise that neither injury nor retaliation is ever right⁵¹. The Stoic tradition as Long presents it ranks man’s prime principle as social, then the rational rule over the body, then freedom from error⁵². Kant pursues the question with unequalled rigour. His work aims to seek out and establish the supreme principle of morality⁵³. That principle cannot be drawn from experience. Duty rests on principles of reason that are a priori, known prior to and independent of experience, and these determine the will^54,55. Moral conceptions originate in reason, and their very purity is what fits them to be supreme practical principles⁵⁶.

Kant first states the principle as the requirement that one’s maxim be fit to become universal law⁵⁷. The categorical imperative is, in his terms, a synthetic a priori proposition: it adds something to the concept of a rational will rather than merely analysing it, yet it does not rest on experience, and its possibility demands profound study⁵⁸. Kant holds that it contains the principle of all duty⁵⁹. Practical principles, he argues, are either formal or material. Ends that are merely relative yield only hypothetical imperatives, while an end of absolute worth grounds a categorical one⁶⁰. Without such an end there would be no supreme practical principle at all⁶¹. That end is rational nature, from which all laws of the will are deduced⁶². Humanity as an end in itself is likewise drawn from pure reason and leads to the principle of universal legislation⁶³. The three formulae are, he says, one law, differing in form, matter and totality⁶⁴. Treating rational beings as ends is identical with acting on a universally valid maxim⁶⁵. The moral principle grounds the actions of rational beings as natural law grounds phenomena⁶⁶.

Mill offers a contrasting kind of first principle. For him the principle of utility became the keystone that united his beliefs and gave unity to his conceptions⁶⁷. Kant insists the supreme principle must be independent of experience. Mill prizes utility for its power to organize a whole outlook.

The moralists also care how a principle is held, and not only what it is. Epictetus teaches that a principle becomes one’s own only by maintaining it daily, hearing it maintained and living by it⁶⁸. Principles are to be practised rather than discussed⁶⁹, and right principles require contentment with being what one is rather than seeming⁷⁰. Marcus Aurelius bids us keep our principles ready, as a physician keeps his instruments, for dealing with things divine and human⁷¹. Pascal notes that principles and consequences, roots and fruits, are led by the same master⁷². Carlyle traces false action to false speculation and hopes that true principles inspiring society would let its disorders be remedied⁷³. Emerson declares that nothing can bring peace but the triumph of principles⁷⁴.

In politics the question becomes one of rigidity against circumstance. Winthrop holds that every commonwealth has fundamentals from which particular cases are deduced. A general rule suffices, he argues, even though no rule can cover every case⁷⁵. Penn trusts that if reason supports a principle, nothing can rightly withstand it⁷⁶. Mill states one simple principle to govern society’s compulsion and control of the individual⁷⁷. Burke is the great dissenter from abstraction. Political principles, he argues, take their character and effect from circumstances, not from metaphysical abstraction stripped of every relation⁷⁸. Extreme principles that cannot be applied to real cases lead men to think lightly of all public principle⁷⁹. Burke does not reject principle as such. The best legislators establish a sure ruling principle and leave it to operate⁸⁰, and order and economy are stable principles even while particular arrangements vary with circumstances⁸¹. Macaulay warns that men err when they abandon eternal principles for accidental associations⁸². Emerson holds that principles accomplish what expedients cannot⁸³, though he remarks dryly that the English cannot read a principle except by the light of fagots and burning towns⁸⁴.

Finally there is the want of principle. Mill insists that whoever professes a principle should go the whole length of it⁸⁵. Lowell’s satirical speaker openly declares that he has no principle, only interest, and follows whatever pays⁸⁶. That figure shows by contrast what all the others assume: that having a starting point one will not trade away belongs to integrity as well as to logic.

Several questions remain open across these texts. Are first principles seen by intuition, as Pascal holds, or found innately and deduced from, as Descartes holds? Or does no single principle carry special authority, as Hume argues? Does the ascent toward higher principles end in a resting-place, as Socrates hoped, or go on without end, as Emerson suspected? Can a moral principle be established a priori, as Kant claims, or does it earn its standing by unifying experience, as utility did for Mill? And can a principle in politics be held firmly without being stripped of the circumstances that give it meaning, as Burke demanded? The authors agree only that something must be assumed, and that how one assumes it matters greatly.