Can’t & Won’t: Two Different Words

It seems to be the case that people are confused about the definitions of can’t and won’t. I think this confusion is problematic. By using these terms interchangeably, or in the wrong way, one creates a psychological problem for oneself by conceiving of one’s situation incorrectly. So, this rant isn’t about clarity of language so much as it is about psychological, mental health. Once we understand the difference between can’t and won’t, we can employ these terms correctly and deal reality as it actually is. In order to understand the difference between can’t and won’t, begin by considering these two sentences:

(A) I can’t have a baby.
(B) I won’t have a baby.

Ponder those for a moment. What is the difference between A and B?

CAN’T indicates an impossibility. If I can’t do X, then it is impossible for me to do X.
One can translate any utterance of “I can’t X” with “It is impossible for me to X”.

WON’T indicates a lack of willingness or volition, a choosing otherwise. If I won’t do X, then I am unwilling to do X.
One can translate any utterance of “I won’t X” with “I am unwilling to X.”

Now that we’ve squared away those definitions, let’s test what we’ve learned by considering these pairs of sentences to determine the sentence in each pair that utilizes the term can’t / won’t correctly:

(A1) I can’t have a baby, because of my hysterectomy.
(A2) I can’t have a baby, because I am a busy lawyer.

(B1) I won’t have a baby, because of my hysterectomy.
(B2) I won’t have a baby, because I am a busy lawyer.

A1 and B2 are linguistically correct statements. A2 and B1 are wrongheaded nonsense. Let’s assess each sentence.

A1: A1 correctly indicates an impossibility. A hysterectomy is the surgical removal of a uterus. A uterus is required for having a baby. It is impossible for a woman who has no uterus to have a baby. Therefore, it is correct to say that hysterectomy woman CAN’T have a baby.

B2: B2 confuses impossibility with unwillingness. Since some lawyers have babies it is incorrect to state that it is impossible for a lawyer to have a baby.

B1: Since a hysterectomy renders an individual incapable of having a baby, it is incorrect to say that hysterectomy woman won’t have a baby. While there is no baby to be had, the lack of a baby does not result from a lack of desire or willingness. Instead, the lack of a baby results from an impossibility of there being a baby.

B2: B2 correctly indicates a lack of willingness. It is possible for a lawyer to have a baby. Therefore, the won’t in B2 correctly identifies a lack of willingness instead of a lack of possibility.

Having assessed the definitions of can’t and won’t via these examples, we now understand the difference between can’t and won’t, and the situations in which each term can be correctly utilized. Can’t indicates an impossibility whereas won’t indicates a lack of willingness.


The Moral "Problem":

One nagging problem for the can’t / won’t distinction is the mistaken thought that a relation exists between morality/ethics and possibility. Some individuals, for example, would argue that a Christian can’t eat shrimp, because of Leviticus 11: 9 – 12. The attempt is to smuggle ethical or moral considerations into one’s conception of possibility. The argument goes like this: Even if a Christian could perform the physical actions require to consume shrimp, the belief in Leviticus would render this act to be impossible.

Which, you know, is moronic.

The answer to this problem is to ask why shrimp consumption is impossible under the Christian schema. When the Christian replies, “It is impossible because the Bible says ‘thall shall not’.” one can calmly remind the Christian that “shall” is a version of “should” and Should Is A Funny Word. The Bible’s shall does not undermine one’s ability to consume shrimp but rather it elicits an emotive response that causes an unwillingness to consume shrimp. This lack of consumption is based on an emotive response and so it falls under the purview of won’t. Remember our translations:

“I can’t X.” = “It is impossible for me to X.”
“I won’t X.” = “I am unwilling to X.”

If a person insists that their ethical or moral code creates an impossibility, rather than an unwillingness, then you may calmly reply: “So, your ethical / moral code is like having a hysterectomy, only instead of your uterus being removed, your physical ability to chew and swallow shrimp has been removed?”

If they affirm that claim, then we walk away. Slowly. Without turning our backs on them. Because they are fucking crazy people.


I think it helpful to clearly understand the meanings of the words we use, and understand the impact our linguistic utterances have on our understanding of reality. If an individual continually says “I can’t X” then that person is reinforcing the notion that X is an impossibility. But if we assess X, determine that it is not impossible, and begin to say “I won’t X” instead, then we can begin to deal with one’s actual relation to X, rather than one’s confused and mistaken understanding of the situation.

The only problem lies in discerning possibility. But that is for another rant.