Not true. That is what Abraham Maslow spent his life trying to tell us. People have needs. Physiological ones (air, water), and also psychological ones (challenges, self-esteem).

Therefore, we can know a want from a need because a need is anything that if you were to go without it, would result in your death or stunted growth.

This piece, like Walden, is about how we can trade what we have mistaken for physiological needs for legitimate psychological needs.

I think ryanwanger's original statement is a sort of a false dichotomy. I don't think you can divide things into "luxuries" and "necessities" without a context. What might be seen as a luxury from one point of view might be a necessity from another point of view.

Drawing on what aspirant said, Maslow's hierarchy of needs is a very good way to provide that context: at the level of physiological needs, you can consider "safety" level needs as "luxuries"; on the other hand, you would consider them as "necessities" from the "love/belonging" level.