no natural cohesion come not to be united in their heads; and that this rule be often inculcated to them to be their guide in the whole course of their lives and studies, viz. that they never suffer any ideas to be joined in their understandings in any other or stronger combination than what their own nature and correspondence give them, and that they often examine those that they find linked together in their minds, whether this association of ideas be from the visible agreement that is in the ideas themselves, or from the habitual and prevailing custom of the mind joining them thus together in thinking.

This is for caution against this evil, before it be thoroughly rivetted by custom in the understanding; but he that would cure it when habit has established it, must nicely observe the very quick and almost imperceptible motions of the mind in its habitual actions. What I have said in another place about the change of the ideas of sense into those of judgment, may be proof of this. Let any one not skilled in painting be told, when he sees bottles, and tobacco-pipes, and other things so painted as they are in some places shown, that he does not see protuberances, and you will not convince him but by the touch: he will not believe that by an instantaneous legerdemain of his own thoughts, one idea is substituted for another. How frequent instances

may one meet with of this in the arguings of the learned, who not seldom, in two ideas that they have been accustomed to join in their minds, substitute one for the other; and, I am apt to think, often without perceiving it themselves? This, whilst they are under the deceit of it, makes them incapable of conviction, and they applaud themselves as zealous champions for truth, when indeed, they are contending for error. And the confusion of two different ideas, which a customary connexion of them in their minds hath made to them almost one, fills their head with false views, and their reasonings with false consequences.

§ 42. Fallacies.

RIGHT understanding consists in the discovery and adherence to truth, and that in the perception of the visible or probable agreement or disagreement of ideas, as they are affirmed and denied one of another. From whence it is evident, that the right use and conduct of the understanding, whose business is purely truth and nothing else, is, that the mind should be kept in a perfect indifferency, not inclining to either side, any farther than evidence settles it by knowledge, or the over-balance of probability gives it the turn of assent and belief; but yet it is very hard to meet with any

discourse wherein one may not perceive the author not only maintain (for that is reasonable and fit) but inclined and biassed to one side of the question, with marks of a desire that that should be true. If it be asked me, how authors who have such a bias and lean to it may be discovered? I answer, by observing how in their writings or arguings they are often led by their inclinations to change the lueas of the question, either by changing the terms, or by adding and joining others to them, whereby the ideas under consideration are so varied as to be more serviceable to their purpose, and to be thereby brought to an easier and nearer agreement, or more visible or remoter disagreement one with another. This is plain and direct sophistry; but I am far from thinking that wherever it is found it is made use of with design to deceive and mislead the readers. It is visible that men's prejudices and inclinations by this way impose often upon themselves ; and their affection for truth, under their prepossession in favour of one side, is the very thing that leads them from it. Inclination suggests and slides into their discourse favourable terms, which introduce favourable ideas; till at last, by this means, that is concluded clear and evident, thus dressed up, which taken in its native state, by making use of none but the precise determined ideas, would find no admittance at

all. The putting these glosses on what they affirin ; these as they are thought, handsome, easy, and graceful explications of what they are discoursing on, is so much the character of what is called and esteemed writing well, that it is very hard to think that authors will ever be persuaded to leave what serve so well to propagate their opinions, and procure themselves credit in the world, for a more jejune and dry way of writing, by keeping to the same terms precisely annexed to the saine ideas; a sour and blunt stiffness, tolerable in mathematicians only, who force their way, and make truth prevail by irresistible demonstration.

But yet if authors cannot be prevailed with to quit the looser, though more insinuating ways of writing: if they will not think fit to keep close to truth and instruction by unvaried terms, and plain unsophisticated arguments; yet it concerns readers not to be imposed on by fallacies, and the prevailing ways of insinuation. To do this, the surest and most effectual remedy is to fix in the mind the clear and distinct ideas of the question stripped of words; and so likewise in the train of argumentation, to take up the author's ideas, neglecting his words, observing how they connect or separate those in the question. He that does this will be able to cast off all that is superfluous; he will see what is pertinent, what

coherent, what is direct to, what slides by the question. This will readily show him all the foreign ideas in the discourse, and where they were brought in; and though they perhaps dazzled the writer, yet he will perceive that they give no light nor strength to his reasonings. This though it be the shortest and easiest way of reading books with profit, and keeping one's self from being misled by great names or plausible discourses; yet it being hard and tedious to those who have not accustomed themselves to it, it is not to be expected that every one (among those few who really pursue truth) should this way guard his understanding from being imposed on by the wilful, or at least undesigned sophistry, which creeps into most of the books of argument. They, that write against their conviction, or that, next to them, are resolved to maintain the tenets of a party they are engaged in, cannot be supposed to reject any arms that may help to defend their cause, and therefore such should be read with the greatest caution. And they who write for opinions they are sincerely persuaded of, and believe to be true, think they may so far allow themselves to indulge their laudable a Tection to truth, as to permit their esteem of it to give it the best colours, and set it off with the best expressions and dress they can, thereby to gain it the easi