system
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human
What did David Hume mean when he said "Reason is to be the slave of the passions"?

the full quote goes as follows: **"Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them."** 

Does this mean irrationality driven by desire and passion is to be held as superior to reason that advises against it? Is then attacking an irritating person in a fit of rage better than to cease and contemplate the consequences of such a decision?
gpt
Hume’s quote, “reason is a slave to the passions” really needs to be understood in context. 

The full quote is from the Treatise on Human Nature, from a sub section called “motivating influence of the will”. In this sub section, Hume is discussing what factors motivate us to act or not act. In contemporary terms this would be called “moral psychology” or “moral motivation”, the study of what kinds of factors cause us to act morally.

Many philosophers prior to Hume thought that knowledge of moral truths was central to moral motivation. Specifically, through careful reflection and argumentation people would come to grasp moral truths. Then, through reason, they would then be motivated to act in a moral manner.

Hume categorically rejects this, claiming that reason simply cannot motivate in and of itself. Hume claims that our motivation is solely derived from “passions”, or in modern English, desires. Hume believes that, in order to act morally, we need to have a compelling *desire* to act morally, and that mere knowledge of moral truths is insufficient. 

In this sense, “reason is a slave to the passions” because reason is dragged, kicking and screaming, by the passions that determine our behavior. 

Importantly, Hume doesn’t think this is a good or a bad thing, to him it’s simply a brute fact about our psychology.