Stephen Wang in Philosophy Now magazine.
Matthieu [in The Age of Reason] wants to justify his actions and base them on good reasons, or at least on some overwhelming desire; but by interrogating his motives, by trying to establish whether they are compelling, he distances himself from them.
This exposes the extent to which how [for some of us] the more you attempt to think through a situation looking for reason and motive and meaning, the more you actually come to things like dasein, conflicting goods and political economy.
The part about "overwhelming desire" seems more in sync with the libido, with instinct, with those deep down inside drives the human brain is notorious for. Just go where they take you, right? Why? Because as soon as you stop to think it all through rationally, to "analyze" it all "philosophically", the more likely you are to end up in the hole that "I" am in all busted up like Humpty Dumpty.
The process of examining his motives shows they have no binding power over his future: the search for obligations leads him to freedom because it uncovers the fact that alternative courses of action are also viable. However costly it seems, the price of being conscious of an identity is a corresponding liberation from that identity, with an ever-present responsibility for continuing or denying that identity. We experience this responsibility through anguish.
All I can say here is that this is more or less what happened to me the more I became immersed in existentialism, deconstruction and semiotics. I began to see how my own objectivist frame of mind was largely just a world of words brought together either by God or political ideology.
And, now, as a moral nihilist, that anguish pops up whenever I am confronted with conflicting goods embedded in this:
If I am always of the opinion that 1] my own values are rooted in dasein and 2] that there are no objective values "I" can reach, then every time I make one particular moral/political leap, I am admitting that I might have gone in the other direction...or that I might just as well have gone in the other direction. Then "I" begins to fracture and fragment to the point there is nothing able to actually keep it all together. At least not with respect to choosing sides morally and politically.
"I" am no longer able to think myself up out of it.
This is not just a point about the fact that our identities change, since anguish does not come about when a past identity is forgotten and a new one adopted. Rather, anguish is a sign that human beings are ‘separated from themselves’, from the identities that constitute who they are now. We can review the present and not just the past, and we have a continual responsibility to recreate our identities through our choices.
You either come to embody this frame of mind or you don't. For me, it's not so much bearing the responsibility of recreating my identity "authentically", but of recognizing how many variables here are either beyond my comprehension or beyond my control. And that no set of behaviors is necessarily either more or less authentic. The "nausea" is derived from the manner in which I construe "I" as the fractured and fragmented embodiment of dasein.