funkyderek,
It's clearly both imaginable and conceivable - but not really likely.
How would you know that it is not likely? Would you care to put a probablity on it?
If these dimensions exist, it seems they are "rolled up" so small that nothing could live in them or travel through them.
And, you've been there, have you? If you are refferring to biological life your statement would make sense, since these dimensions are far smaller than organic molecules. But what if life can also be arranged in a completely different manner, one that is wholly unlike anything that we can presently imagine.
They are not gateways to other realities or sci-fi type "dimensions".
First you say that onacruse's philosophical speculation is "clearly both imaginable and conceivable" and then you make the categorical statement as I have copied above. You meant to say that you do not currently believe that the extra dimensions of string theory are gateways to other realities, and that modern science has yet to give us reason to believe so. It would be rather unscientific to feign knowledge in the absence of evidence one way or the other.
We are creatures that love to believe that we have everything nicely figured out, or at least the most important things. The theist goes under the assumption that there is a God and a spiritual reality and the atheist is quite comfortable working from a completely materialist paradigm. The fact of the matter is that there is so much we simply to not understand and it would be the height of arrogance to proclaim as reality that which is only speculation as well as dismiss as unreal what is only imaginatively hypothetical. Science is, and should be, a conservative enterprise, but it is interesting to note that many of the great advances in our knowledge have come from those who pushed the boundaries of what is "proper" science. Not too long ago anyone who might have described subatomic reality the way modern quantum physicists do would have been laughed at with derision and been proclaimed a believer in the occult.
A hundred years from now people will be rather amused at what we believe is not possible.
Bradley