Mr. Hobbs, in his Discourse of Human Nature,  which, in my humble Opinion, is much the best of all his Works, after some very curious Observations upon Laughter, concludes thus:
'The Passion of Laughter is nothing else but sudden Glory arising from some sudden Conception of some Eminency in ourselves by Comparison with the Infirmity of others, or with our own formerly: For Men laugh at the Follies of themselves past, when they come suddenly to Remembrance, except they bring with them any present Dishonour.'
According to this Author, therefore, when we hear a Man laugh excessively, instead of saying he is very Merry, we ought to tell him he is very Proud. And, indeed, if we look into the bottom of this Matter, we shall meet with many Observations to confirm us in his Opinion. Every one laughs at some Body that is in an inferior State of Folly to himself. It was formerly the Custom for every great House in England to keep a tame Fool dressed in Petticoats, that the Heir of the Family might have an Opportunity of joking upon him, and diverting himself with his Absurdities. For the same Reason Idiots are still in Request in most of the Courts of Germany, where there is not a Prince of any great Magnificence, who has not two or three dressed, distinguished, undisputed Fools in his Retinue, whom the rest of the Courtiers are always breaking their Jests upon.
The Dutch, who are more famous for their Industry and Application, than for Wit and Humour, hang up in several of their Streets what they call the Sign of the Gaper, that is, the Head of an Idiot dressed in a Cap and Bells, and gaping in a most immoderate manner: This is a standing Jest at Amsterdam.
Thus every one diverts himself with some Person or other that is below him in Point of Understanding, and triumphs in the Superiority of his Genius, whilst he has such Objects of Derision before his Eyes. Mr. Dennis has very well expressed this in a Couple of humourous Lines, which are part of a Translation of a Satire in Monsieur Boileau. 
Thus one Fool lolls his Tongue out at another, And shakes his empty Noddle at his Brother.
Mr. Hobbs's Reflection gives us the Reason why the insignificant People above-mentioned are Stirrers up of Laughter among Men of a gross Taste: But as the more understanding Part of Mankind do not find their Risibility affected by such ordinary Objects, it may be worth the while to examine into the several Provocatives of Laughter in Men of superior Sense and Knowledge.
In the first Place I must observe, that there is a Set of merry Drolls, whom the common People of all Countries admire, and seem to love so well, that they could eat them, according to the old Proverb: I mean those circumforaneous Wits whom every Nation calls by the Name of that Dish of Meat which it loves best. In Holland they are termed Pickled Herrings; in France, Jean Pottages; in Italy, Maccaronies; and in Great Britain, Jack Puddings. These merry Wags, from whatsoever Food they receive their Titles, that they may make their Audiences laugh, always appear in a Fool's Coat, and commit such Blunders and Mistakes in every Step they take, and every Word they utter, as those who listen to them would be ashamed of.
But this little Triumph of the Understanding, under the Disguise of Laughter, is no where more visible than in that Custom which prevails every where among us on the first Day of the present Month, when every Body takes it in his Head to make as many Fools as he can. In proportion as there are more Follies discovered, so there is more Laughter raised on this Day than on any other in the whole Year. A Neighbour of mine, who is a Haberdasher by Trade, and a very shallow conceited Fellow, makes his Boasts that for these ten Years successively he has not made less than an hundred April Fools. My Landlady had a falling out with him about a Fortnight ago, for sending every one of her Children upon some Sleeveless Errand, as she terms it. Her eldest Son went to buy an Halfpenny worth of Inkle at a Shoe-maker's; the eldest Daughter was dispatch'd half a Mile to see a Monster; and, in short, the whole Family of innocent Children made April Fools. Nay, my Landlady herself did not escape him. This empty Fellow has laughed upon these Conceits ever since.
This Art of Wit is well enough, when confined to one Day in a Twelvemonth; but there is an ingenious Tribe of Men sprung up of late Years, who are for making April Fools every Day in the Year. These Gentlemen are commonly distinguished by the Name of Biters; a Race of Men that are perpetually employed in laughing at those Mistakes which are of their own Production.
Thus we see, in proportion as one Man is more refined than another, he chooses his Fool out of a lower or higher Class of Mankind: or, to speak in a more Philosophical Language, That secret Elation and Pride of Heart, which is generally called Laughter, arises in him from his comparing himself with an Object below him, whether it so happens that it be a Natural or an Artificial Fool. It is indeed very possible, that the Persons we laugh at may in the main of their Characters be much wiser Men than ourselves; but if they would have us laugh at them, they must fall short of us in those Respects which stir up this Passion.
I am afraid I shall appear too Abstracted in my Speculations, if I shew that when a Man of Wit makes us laugh, it is by betraying some Oddness or Infirmity in his own Character, or in the Representation which he makes of others; and that when we laugh at a Brute or even [at] an inanimate thing, it is at some Action or Incident that bears a remote Analogy to any Blunder or Absurdity in reasonable Creatures.
But to come into common Life: I shall pass by the Consideration of those Stage Coxcombs that are able to shake a whole Audience, and take notice of a particular sort of Men who are such Provokers of Mirth in Conversation, that it is impossible for a Club or Merry-meeting to subsist without them; I mean, those honest Gentlemen that are always exposed to the Wit and Raillery of their Well-wishers and Companions; that are pelted by Men, Women, and Children, Friends and Foes, and, in a word, stand as Butts in Conversation, for every one to shoot at that pleases. I know several of these Butts, who are Men of Wit and Sense, though by some odd Turn of Humour, some unlucky Cast in their Person or Behaviour, they have always the Misfortune to make the Company merry. The Truth of it is, a Man is not qualified for a Butt, who has not a good deal of Wit and Vivacity, even in the ridiculous side of his Character. A stupid Butt is only fit for the Conversation of ordinary People: Men of Wit require one that will give them Play, and bestir himself in the absurd Part of his Behaviour. A Butt with these Accomplishments frequently gets the Laugh of his side, and turns the Ridicule upon him that attacks him. Sir John Falstaff was an Hero of this Species, and gives a good Description of himself in his Capacity of a Butt, after the following manner; Men of all Sorts (says that merry Knight) take a pride to gird at me. The Brain of Man is not able to invent any thing that tends to Laughter more than I invent, or is invented on me. I am not only Witty in my self, but the Cause that Wit is in other Men. 
[Footnote 1: Chap. ix. § 13. Thomas Hobbes's 'Human Nature' was published in 1650. He died in 1679, aged 91.]
[Footnote 2: Boileau's 4th satire. John Dennis was at this time a leading critic of the French school, to whom Pope afterwards attached lasting ridicule. He died in 1734, aged 77.]
[Footnote 3: 'Henry IV Part II' Act I § 2.]Translation of motto: