Akrasia
acrasia · weakness of will
Acting against your own better judgment — knowing the better course and taking the worse one, which Socrates argued is impossible and everyone else has observed constantly.
In practice
You decide on Sunday to make the difficult call on Monday, and on Monday you do something else that is genuinely useful. Nothing about the judgment changed; the moment did.
The common mistake
Treating it as a failure of information or motivation. The puzzle is that the person has the judgment and the motivation to act on it and does otherwise anyway.
Akrasia is weakness of will: doing what you judge you should not, while judging it. The Greek means lacking command, and the puzzle is not whether it happens but how it can.
Socrates denies it
Socrates argued that nobody knowingly does wrong. If you genuinely judge one course better and still take the other, you did not really have the knowledge — you had an opinion overwhelmed by the appearance of pleasure.
The position follows from treating virtue as a kind of knowledge, and it has the merit of consistency. Its cost is that it denies something everyone believes they have experienced.
Aristotle's analysis
Aristotle wanted to save the phenomenon. His account distinguishes having knowledge from using it in the moment. The akratic person holds the right general principle and fails to apply it to the case in front of them, because appetite has made the particular vivid and the principle abstract.
He also distinguishes the akratic from the intemperate. The intemperate person acts wrongly and endorses it; the akratic acts wrongly against their own view and regrets it. Only the second is torn, which is what makes it a puzzle about the structure of agency rather than about bad character.
Why it still matters
It is the clearest case where the picture of a person as a single reasoning agent breaks down. If you can want what you judge you should not want, then either judgment and motivation are separable, or the self is not unified enough for the question to have a clean answer.
Modern treatments frame it through discounting — see present bias — where the preference genuinely reverses as the moment approaches. That explains the behavior without requiring anyone to act against a judgment they hold at the time, which some philosophers regard as dissolving the puzzle and others as changing the subject.
In practice
Every commitment device is a response to it: deciding in advance and making the decision expensive to reverse, because the person making the plan and the person executing it cannot be relied on to agree. See the promise ratio.
Questions
What is akrasia?
Weakness of will — acting against your own better judgment while holding it. The Greek term means lacking command over oneself.
Why did Socrates deny akrasia is possible?
Because he treated virtue as knowledge. If you truly know one course is better you will take it, so apparent weakness of will is really ignorance dressed as knowledge.
How did Aristotle explain it?
By distinguishing having knowledge from using it in the moment. The akratic person holds the right principle and fails to apply it, because appetite makes the particular vivid and the principle abstract.