My reading of this is that he is saying that the mind is withdrawing from the material world. — Hay Digger

The way I understand it is different. Suppose I am considering what to have for lunch. Maybe beans on toast, or maybe omelette. Neither of these is part of the material world - there are eggs in the kitchen, but no omelette. To consider acting is not to act. So it is not a claim that thoughts themselves are immaterial but that what they are about is immaterial, rather as an architect draws plans for a building that does not (yet) exist. The plans are as material as anything, but there is no building and may never be one. Yet oddly, one doesn't complain about how the architect models the world on these grounds.

Thanks Unenlightened. The lunch and architect examples are very useful. But I'm still somewhat confused:

To consider acting is not to act. — unenlightened

Is it not? Considering is a verb; does that not make it (and thus considering to act) an act in itself? It requires the passage of time. Time in which material changes take place. This probably highlights my misunderstanding of Sartre's philosophy. I'll try to reply with a better example in future, once I've reflected on your examples a little longer.

Is it not? Considering is a verb; does that not make it (and thus considering to act) an act in itself? It requires the passage of time. Time in which material changes take place. This probably highlights my misunderstanding of Sartre's philosophy. — Hay Digger

Yes you're right. I sacrificed exactitude to brevity there. Allow me to correct myself. To consider acting is not the act under consideration except on rare occasions such as this, when it's philosophy, and other occasions when it is prevarication.

But I think Sartre would also posit a condition of presence, say of an artist looking, acting, considering, deciding, responding moment to moment a creative wholeness. In a sense it is almost universal to conceive the scholar as habitually absent- minded, absent from the full world, and contemplating an abstraction. I think Sartre, living through war, occupation and so on, found the material world interrupting that life of philosophical withdrawal in ways that he could not ignore, and it is thus the necessity to 'get real' that he tries to incorporate into his ethics. He would much prefer to drink coffee and chain-smoke while pontificating in a pavement cafe, bur finds himself obliged to actually man the barricades, or or else betray himself.

Thanks Unenlightened. I'll reflect on all that.