Well, I think that, like a host of similar proposals, it has a certain currency among the string theory community (and maybe particle theory more broadly), but most physicists view it with deep suspicion. Among the problems, of course, is that you can't enumerate options. I think you also start to really multiply questionable assumptions. And then of course, there's the fact that historically, it has a pretty miserable track record -- physics kept turning up behaviors that nobody had thought of. (Related to the first point).

Peter Woit's blog is something of a clearinghouse on discussions of any of these proposals, and the comments section can be quite good. I wasn't able to find a discussion specifically of that proposal of Linde's, though (at least in four minutes' searching).

I think that there are areas of science where this is perfectly acceptable; cosmology and astrophysics spring to my mind.

In paradise?

Can you give an example of its being acceptable in those fields, Pepijn?

Sorry, that was in response to fullham: "Apologies, but I think it is clear where the trouble originated."

Maybe I misinterpret the term 'options', but my general point is that these disciplines do not have access to repeatable experiments with controlled parameters. They rather rely on spectra of various forms of radiation reaching the earth. Knowledge is gained by coming up with models of processes in the universe which agree with the data collected by observatories, which allows the scientist to rule out options. In that sense all knowledge in these disciplines, from the composition of stellar atmospheres to the constituents of dark matter could be said to stem from eliminating options.

Having said that, it certainly is also true that there is a different quality to the knowledge gained. The model for stellar atmospheres is, to the best of my knowledge not particularly controversial, dark matter on the other hand more so.

Even in astronomy, despite there only being one observable universe, a new hypothesis should still make predictions about observations that have yet to be made.

For instance when the existence of exo-planets was hypothesized this lead to the prediction that we should observe wobbles in the Doppler shift of stars due to the gravitational influence of those exo-planets, as well as periods of reduced brightness when those exo-planets pass between us and their star, blocking some of its radiation. Subsequently those observations were indeed made. The whole reason to start making those observations in the first place was because they could possible falsify the hypothesis that exo-planets exist.

The experimental discovery of gravitational lensing after it had already been predicted by Einstein is a similar example of how a new theory should prompt new observations that can possibly falsify it.

This is distinctly different from the current state of string theory, where the theory may fit already existing observations but doesn't make any predictions that would allow it to be falsified by new observations. It's perfectly fine that while trying to formulate a new theory one can't immediately meet the requirement of making predictions, as long as you consider the theory formulation a work in progress. Scientifically you can't put such an unfinished, unfalsifiable theory on equal footing with other theories that were vulnerable to falsification by comparison of their predictions and new observations.

This unfinished characteristic of string theory will prompt some people to say it is not a scientific theory. I would say that is a bit harsh. Sure, an apple pie is not an apple pie until you've baked it, but even pre-baking it already carries many characteristics of a true apple pie. It still won't be as delicious though. Personally I certainly think string theorist should be regarded as scientists. However after many decades of failing to find the oven, rather than arguing that apple pie doesn't need to be baked, they should quit being so defensive and just accept that some people rightfully doubt whether they will ever serve the pie they promised.

It does make predictions though. Doesn't it predict fuzzy black holes and gauge/gravity duality?