Nigel of Kiwi Pundit explains why he doesn't think much of the notion of substantive freedom. Unfortunately, his post exhibits some serious misunderstandings. (It doesn't help that he offers his readers no direct links to the ideas of mine to which he claims to be responding.)
For example, it simply isn't true that substantive freedom "means the same as standard of living". This conflates the distinct concepts of opportunities and material welfare. The difference is made clear by Nigel's own case of the well-provided slave. Having a big-screen T.V. is no guarantee that you are able to pursue the life you want to live. The slave might be rich, but insofar as he is forced to pick cotton, and otherwise do his master's bidding, then he lacks substantive freedom.
The most we can say is that he has more freedom (because more opportunities) than a slave who is locked in a dungeon all day and so prevented from pursuing anything he values in life. Perhaps the first slave is at least free to develop his mind, look after his family, enjoy some leisure, etc. But one cannot conclude from this that he is "free", simpliciter. An important implication of my position, after all, is that there are degrees of freedom -- it's not an "all or nothing" binary concept.
So, to clarify: although increasing the standard of living will generally tend to increase the number of valuable opportunities open to people, and thus their 'substantive freedom', these are nevertheless distinct concepts, and ought not to be conflated.
Nigel goes on to misapply my "well" example. He thinks it involves an "unspoken assumption" (though one he agrees with) that "B ought to release A from the well". He then goes on to interpret it as concerning "what the government can justify forcing us to do". But that is not the purpose of the well example. I use it merely to demonstrate that negative freedom, i.e. freedom from interference, is not the (only) sort of freedom that we really value. (If you think the man stuck down the well lacks freedom, then you are forced to go beyond negative freedom, for he has no lack of that.) That is all. Period. It is not about morality, or politics, or justified coercion. It is simply about the concept of freedom. It makes no assumptions about whether freedom ought to be promoted. That's a separate question. And the well example is surely too unusual to serve as a practical example concerning political intervention (as Nigel's fumbling attempts demonstrate). Better examples might involve education or basic healthcare rather than wells.
The political question -- as independent from the conceptual question -- is addressed in my post: Enabling Humanity. There I argue that we should take the promotion of substantive freedom (rather than negative freedom, or even material welfare) as our core political value. That is, we should aim to enable as many people as possible to lead the lives they want to live. I leave open the empirical question of how best to achieve this. (Obviously it will need to take incentives and similar issues into account.)
I do tentatively suggest that an unconditional basic income, to complement the market economy, would likely be beneficial in this respect. But Nigel hasn't addressed any of the arguments I present in the linked posts (as opposed to his blanket dismissal of "socialist policies"). Indeed, he hasn't really addressed any of my arguments at all.