WHEN man reasoneth,he does nothing else but conceive a sum total,from addition of parcels;or conceive a remainder,from subtraction of one sum from another:which,if it be done by words,is conceiving of the consequence of the names of all the parts,to the name of the whole;or from the names of the whole and one part,to the name of the other part.And though in some things,as in numbers,besides adding and subtracting,men name other operations,as multiplying and dividing;yet they are the same:for multiplication is but adding together of things equal;and division,but subtracting of one thing,as often as we can.These operations are not incident to numbers only,but to all manner of things that can be added together,and taken one out of another.For as arithmeticians teach to add and subtract in numbers,so the geometricians teach the same in lines,figures (solid and superficial),angles,proportions,times,degrees of swiftness,force,power,and the like;the logicians teach the same in consequences of words,adding together two names to make an affirmation,and two affirmations to make a syllogism,and many syllogisms to make a demonstration;and from the sum,or conclusion of a syllogism,they subtract one proposition to find the other.Writers of politics add together pactions to find men's duties;and lawyers,laws and facts to find what is right and wrong in the actions of private men.In sum,in what matter soever there is place for addition and subtraction,there also is place for reason;and where these have no place,there reason has nothing at all to do.
Out of all which we may define (that is to say determine)what that is which is meant by this word reason when we reckon it amongst the faculties of the mind.For reason,in this sense,is nothing but reckoning (that is,adding and subtracting)of the consequences of general names agreed upon for the marking and signifying of our thoughts;I say marking them,when we reckon by ourselves;and signifying,when we demonstrate or approve our reckonings to other men.
And as in arithmetic unpractised men must,and professors themselves may often,err,and cast up false;so also in any other subject of reasoning,the ablest,most attentive,and most practised men may deceive themselves,and infer false conclusions;not but that reason itself is always right reason,as well as arithmetic is a certain and infallible art:but no one man's reason,nor the reason of any one number of men,makes the certainty;no more than an account is therefore well cast up because a great many men have unanimously approved it.And therefore,as when there is a controversy in an account,the parties must by their own accord set up for right reason the reason of some arbitrator,or judge,to whose sentence they will both stand,or their controversy must either come to blows,or be undecided,for want of a right reason constituted by Nature;so is it also in all debates of what kind soever:and when men that think themselves wiser than all others clamour and demand right reason for judge,yet seek no more but that things should be determined by no other men's reason but their own,it is as intolerable in the society of men,as it is in play after trump is turned to use for trump on every occasion that suit whereof they have most in their hand.For they do nothing else,that will have every of their passions,as it comes to bear sway in them,to be taken for right reason,and that in their own controversies:bewraying their want of right reason by the claim they lay to it.
The use and end of reason is not the finding of the sum and truth of one,or a few consequences,remote from the first definitions and settled significations of names;but to begin at these,and proceed from one consequence to another.For there can be no certainty of the last conclusion without a certainty of all those affirmations and negations on which it was grounded and inferred.As when a master of a family,in taking an account,casteth up the sums of all the bills of expense into one sum;and not regarding how each bill is summed up,by those that give them in account,nor what it is he pays for,he advantages himself no more than if he allowed the account in gross,trusting to every of the accountant's skill and honesty:
so also in reasoning of all other things,he that takes up conclusions on the trust of authors,and doth not fetch them from the first items in every reckoning (which are the significations of names settled by definitions),loses his labour,and does not know anything,but only believeth.
When a man reckons without the use of words,which may be done in particular things,as when upon the sight of any one thing,we conjecture what was likely to have preceded,or is likely to follow upon it;if that which he thought likely to follow follows not,or that which he thought likely to have preceded it hath not preceded it,this is called error;to which even the most prudent men are subject.But when we reason in words of general signification,and fall upon a general inference which is false;though it be commonly called error,it is indeed an absurdity,or senseless speech.For error is but a deception,in presuming that somewhat is past,or to come;of which,though it were not past,or not to come,yet there was no impossibility discoverable.But when we make a general assertion,unless it be a true one,the possibility of it is inconceivable.And words whereby we conceive nothing but the sound are those we call absurd,insignificant,and nonsense.And therefore if a man should talk to me of a round quadrangle;or accidents of bread in cheese;or immaterial substances;or of a free subject;a free will;or any free but free from being hindered by opposition;I should not say he were in an error,but that his words were without meaning;that is to say,absurd.