These are personal reflections and don’t reflect any official stance of CEA or Giving What We Can (I work for CEA). I’ve talked to some of my colleagues. Some of them have had similar thoughts, others haven’t.
When I was 21 (I’m now 27), I took the Giving What We Can pledge to donate 10% of my income to effective charities. This was a pretty big commitment, and worth taking some time to think about. My biggest worry was that I would regret it.
I’ve seen some discussion of this worry elsewhere by people considering taking the pledge (see point 2 in Alyssa Vance’s post). I thought it would be helpful to talk about my reasoning in case it resonates with others.
At first, I was tempted by the idea that regret wouldn’t matter – future selfish me is an idiot. And to the extent that I could bind future selfish me that would be just fine. But on reflection, this didn’t seem right to me – from current me’s perspective, my misanthropic potential future self would be mistaken. But from future selfish me’s perspective (I presume), current me was an ardent fool. It didn’t seem fair to bind my future self, based on my current self’s first mover advantage. I was confused. So I read some philosophy (as one does).
The situation bears a striking resemblance to Derek Parfit’s story of the young Russian nobleman (paraphrased from Parfit, 1973, p. 146):
A young idealistic nobleman knows that he’s set to inherit a large sum of money in the future. Wary of his own fading idealism, he promises his wife that he will donate this money to the socialist party to help the poor. He asks her to hold him to this promise, no matter how much his future self pleads and begs for her to release him.
Now it seemed to me that what the young nobleman does is quite unfair (particularly on his wife but let’s set that aside).
Insofar as the current and future nobleman is a single person, persisting through time, then my conception of rationality  says he should consider his future self’s preferences as well as his current self’s preferences. 
Insofar as the current and future noblemen are different people, then it seems like an unfair restriction on his future self’s choice set. I certainly wouldn’t endorse forcing people to take the pledge who didn’t want to  – so I wouldn’t endorse forcing future me to do something he didn’t want to .
But I took the pledge anyway because I didn’t think that my future self would regret it. Six years on, this has been true so far. There hasn’t yet been a point where I’ve felt even a twinge of regret, and this characterises the vast majority of pledgers I’ve talked to (I acknowledge there may be some selection effect here). If I didn’t take the pledge, I don’t think my future self would regret it either (although I’m less sure about this).  
For me, taking the pledge wasn’t primarily an act of self-binding (restricting my future self). It was an act of self-determination (choosing which of my potential future selves actually came about). I think it changed my life in a positive way. If I hadn’t taken it, I think it’s very likely that my primary goal now wouldn’t be helping people. I hope I would have still done something a bit good – but there’s a decent chance I wouldn’t have.
I think it’s also likely that taking the pledge made me more, rather than less likely to use my career to help others. I don’t really know what it is about making public commitments  that changes how we view ourselves and define our life goals. But it seems to have worked, at least for me.
- This consideration won’t apply to everyone. It depends on a bunch of psychological assumptions about me. But I think it does apply to a lot of people (notwithstanding typical mind fallacy) – so I’m happy the pledge exists, and I’m proud to work at an organisation that promotes it.
- It’s possible that 40 year old me might regret taking the pledge and be bound by it. But I don’t have any good reason to think this is likely.
- This is what I remember going through my head but it was a long time ago, and it’s possible I’ve filled in the gaps post hoc. In any case, I think this reflects my view now.
 I use this term in the weak Humean sense of instrumental rationality, meaning to act consistently with one’s own preferences (altruistic or self-interested) no matter what they are.
 Christine Korsgaard sums up my problem with the nobleman nicely:
“he doesn’t think of his future reasons as reasons… His efforts as a young man are dedicated to insuring that his younger self wins, and his older self loses. His soul is therefore characterized by civil war, and that is why he fails as an agent” (Korsgaard, 2009, p. 29)
 Although I would (in a world in which it was politically feasible and had minimal weird incentive effects) endorse a global redistributive tax, which seems a bit different.
 Assuming it’s not something stupid like smoking. Full disclosure: I smoke.
 These two statements are consistent because my two potential future selves are different people with different sets of preferences. The act of taking the pledge changed which of my future selves would come about.
 I think if I had pledged to give a lot more, it’s more likely that my future self would regret it.
 In fact, for me, it was initially a private commitment – I didn’t talk about if for a couple of years.