'The guilty think all talk is of themselves' meaning & source in The Canterbury Tales

The famous Chaucer phrase 'The guilty think all talk is of themselves' is often quoted, but rarely properly attributed to its source and written in its original form.

It is from 'The Prologue to the Canon's Yeoman's Tale' and in its original Middle English form appears as below in The Canterbury Tales:

While this Yeoman was thus in his talking,
This Canon drew him near, and heard all thing
Which this Yeoman spake, for suspicion
Of menne's speech ever had this Canon:
For Cato saith, that he that guilty is,
Deemeth all things be spoken of him y-wis;

A modern translation of this passage, gives us the well-known quote:

Now while his Yeoman was enlarging thus
In came the Canon, hearing him discuss,
To listen closer; his suspicious head
Distrusted anything that people said.
Cato has said a guilty conscience delves;
The guilty think all talk is of themselves 

The context is that the Canon overhears the Yeoman and asks him to hold his tongue. Indeed part of the Yeoman's tale describes the somewhat dubious business of the Canon who is also an alchemist which explains his likely guilty conscience. 

The meaning of the phrase describes the effect of a guilty conscience, the paranoia of those who have done wrong who fear that they will be exposed and thus suspect that people are talking of them and their deeds.

The passage refers to 'Cato' who coined the phrase that Chaucer refers to. He was Marcus Porcius Cato, Cato the Elder*, who was a Roman soldier, senator and historian and wrote the Carmen de moribus (Poem on morality). This includes the line "Conscius ipse sibi de se putat omnia dici" which can be translated as "The conspirator believes that everything spoken refers to himself." So, not a direct re-quotation, but a rewording of the phrase.

* Not to be confused with his great grandson, Cato the Younger, who was also called 'Marcus Porcius Cato'! 

Meaning of "There is no newe guise, but it was old" in Chaucer's Canterbury Tales

The phrase "There is no newe guise, but it was old" is from the Wife of Bath's tale in Geoffrey Chaucer's The Canterbury Tales.

It's more common rewording in modern English is "There's never a new fashion but it's old".

The phrase itself appears in the following section of the tale where the Wife of Bath describes how "every lusty knight" would dress "T' fight for a lady":

Some will be armed on their legges weel;
Some have an axe, and some a mace of steel.
There is no newe guise, but it was old.
Armed they weren, as I have you told,
Evereach after his opinion.

The meaning is that nearly all ideas come around again and there are few ideas that are genuinely new and fashion, as with ideas, is cyclical. Some are forgotten, some reinvented and some simply recycled over time.

Wife of Bath's Tale, Ellesmere manuscript, c. 1405–1410

Meaning of 'Ful wys is he that kan himselven knowe' in Chaucer's Canterbury Tales

The well-known phrase 'Ful wys is he that kan himselven knowe' was written by Geoffrey Chaucer in his most famous work, The Canterbury Tales.

It appears in 'The Monk's Tale' in the following passage:

Thus starf this worthy myghty Hercules.
Lo, who may truste on Fortune any throwe?
For hym that folweth al this world of prees,
Er he be war, is ofte yleyd ful lowe.
Ful wys is he that kan hymselven knowe.
Beth war, for whan that Fortune list to glose,
Thanne wayteth she her man to overthrowe,
By swich a wey, as he wolde leest suppose.

In modern English, the words translate to what sounds clumsy to our ear 'Full wise is he that can himself know' and might be better phrased as 'He who knows himself is very wise'.

The Monk is describing the death of Hercules who put on a poisoned shirt given to him by an enemy. He then muses on the role of luck and how it can humble even the mightiest warrior. 

Meaning of 'With empty hand men may no hawkes lure' in Chaucer's Canterbury Tales

The phrase 'With empty hand men may no hawkes lure' is from the Prologue to The Wife of Bath's tale in Chaucer's Canterbury Tales. You can read the prologue to her tale in full here.

The context is as follows:

I would no longer in the bed abide,
If that I felt his arm over my side,
Till he had made his ransom unto me,
Then would I suffer him do his nicety.
And therefore every man this tale I tell,
Win whoso may, for all is for to sell;
With empty hand men may no hawkes lure;
For winning would I all his will endure,
And make me a feigned appetite,

It's one of the more delicate phrases to explain, but essentially the wider context is that The Wife of Bath is describing how she uses her body for pleasure and power and to become one her many husbands it requires wealth.

The simple analogy is how a hawk can be lured back to one's hand with some food, so she can be attracted with material things. Some read it more crudely that she accepts money for sex, but equally it can be read as a more nuanced statement of the balance between the sexes in relationships in Chaucer's times.