Who are Hamlet's foils and how do they illuminate his character?

Hamlet's only conspicuous foil is Laertes, the son of Polonius. Laertes is impetuous and headstrong. Unlike Hamlet, Laertes acts without considering the possible consequences. In this respect he is the exact opposite of Hamlet, who procrastinates and meditates until forced to take action against King Claudius in the very last scene of the play. The sharpest contrast between Laertes and Hamlet is to be seen in Act 4, Scene 5, where Laertes impulsively and without adequate preparation leads a mob against Claudius seeking revenge for his father's murder. Laertes is doing what Hamlet should have done. However, the ease with which Claudius pacifies the headstrong Laertes, and actually turns him into a co-conspirator against his stepson, suggests that Hamlet might be the more intelligent and judicious of the two men, and that patience and caution might be understandable in such a delicate undertaking as assassinating a king and establishing a new monarchy.

Horatio is the only other young male who might be considered a foil to Hamlet, but he seems to exist as a character mainly as a friend with whom Hamlet can share his thoughts, feelings and especially his secrets. Rather than being a foil, Horatio is more like Hamlet's alter-ego. Without Horatio to confide in, Hamlet might be forced to talk to himself in additional soliloquies. There are already almost too many of these in the play; more of them might become tiresome and annoying. No doubt Shakespeare had to wrestle with the problem of portraying a man whose conflict was mainly internal and created Horatio in order to dramatize some of that conflict with dialogue.

What are some examples of character foils in Hamlet?

The character foil is a very useful technique for presenting two opposing characters so that they might highlight each other’s differences in temperament, behavior, values, relationships, motives, and so on. Shakespeare employed this literary technique quite adeptly in his dramas, demonstrating how intuitive he was was concerning human nature.

In Hamlet, nearly every character has a foil or two (or three). King Claudius is frequently and openly compared to his predecessor, the brother he murdered. King Hamlet loved his country, his wife, and his son, and he showed that love through protective actions. Even in death, he comes back to warn Hamlet to protect the kingdom and Queen Gertrude from Claudius’s evil behaviors. Claudius, however, has no qualms about killing anyone who gets in his way of having the crown and the queen. Hamlet attempts to show Gertrude the differences between the two men as he holds up a picture of each to her in act 3, scene 4. He says that Claudius is "like a mildewed ear blasting his wholesome brother.” We see the difference clearly, even if Gertrude cannot.

Although most protagonists have a foil, Hamlet actually has several. While the prince’s nature is melancholy and filled with emotional highs and lows, his close friend Horatio is very level-headed and emotionally stable. For example, after Claudius storms guiltily out of the play in act 3, scene 2, Hamlet is erratically happy and energetic, excitedly asking Horatio if he observed Claudius’s guilty response. Horatio calmly replies, “I did very well note him.” We get the sense that Horatio is a little nonplussed by his friend’s inappropriate response. Later, in the graveyard, in act 5, scene 1, Hamlet morosely contemplates the course of Alexander the Great’s body through the earth and into the loam used to stop a beer barrel. Horatio tries to halt the morbid direction of his friend’s thoughts by saying, “Twere to consider too curiously to consider so.” Shakespeare places calm, logical Horatio next to Hamlet to not only act as a leveling presence in the prince’s life, but to highlight Hamlet’s brooding, overly emotional nature.

Another character foil for Hamlet is Laertes. On the surface, they have similar circumstances—a father murdered. Hamlet acknowledges this in act 5, scene 2, when he tells Horatio, “by the image of my cause I see the portraiture of his.” While Hamlet suffers from an inability to act upon his desire for revenge, he contemplates every related thought and opportunity, Laertes is overly rash in his decision-making. Unlike Hamlet, he is willing to damn his own soul to hell for his revenge; he storms the castle in an attempt to kill King Claudius but then succumbs to the king's suggestion to murder Hamlet.

Even Prince Fortinbras of Norway acts as a foil to Hamlet, although though we see little of him in the play. He takes action to expand his future kingdom, bravely commanding an army to fight for land in Poland. Hamlet compares himself to the prince and his army, admiring how they would bravely "go to their graves like beds,” simply because "honor’s at the stake." He admits that he, whose father was murdered and mother ruined, has done nothing, and he uses Fortinbras’s example to spur his own revenge (or at least he contemplates it).

Shakespeare’s Hamlet is rich with other foils, as well, so by the end of the play, he has revealed the psyche of each tragic character.

What is an example of a stock character and a foil in Hamlet?

Shakespeare's longest play is replete with different types of characters. Shakespeare includes stock characters and foils in his tragedies for different purposes, but they often add comic relief 

• Polonius as stock character

Polonius is the older man who is adviser to King Claudius. Once a brilliant man, Polonius now becomes entangled in his thoughts and confused in their direction. Thus, the humor of Polonius arises not from what he says, which is often wise advice, but from the order of his thoughts and his loquaciousness, as well as his timing. For example, in Act II, when Hamlet directs the players to perform a drama that similar to what has happened to his father so that he can watch Claudius and the queen, Polonius interrupts a player who says, "The mobled queen---'" with "that's good" (2.2.465) or other comments such as "This is too long." In this scene, critics feel that Shakespeare pokes fun of his less sophisticated of the audience whose tastes are less developed than what he desires. Polonius is also ridiculous as he exploits his own daughter to learn more about Hamlet so that he can ingratiate himself with the King. 

Providing comic relief, Polonius is a stock character because he represents a type, the older man of former wisdom who, in his failures of not recognizing his debility becomes comical as a meddler and, like other stock character fathers, he exploits his daughter to assist him in his social gain.

• Fortinbras as a foil

In contrast to Hamlet, who has moved only from soliloquy to soliloquy in his deliberation about avenging the death of his beloved father, the young prince Fortinbras of Norway is readily preparing to risk his life for the honor of his father. In Act IV, Hamlet observes of Fortinbras,

Witness this army of such mass and charge,
Led by a delicate and tender prince,
Whose spirit, with divine ambition puffed,
Makes mouths at the invisible event
Exposing what is amoral and unsure
To all that fortune, death, and danger dare,
Even for an eggshell. (4.4.47-53)

It is after this reflection of Hamlet that he delares, "This is I/Hamlet the Dane" (5.1.227),and, inspiried by Fortinbras, takes action to avenge his murdered father.