This double-negative "if you really believe not-X then you're wrong" framing is a bit confusing, so I'll just ask.
Consider the set P of all processes that take a person X1 as input and produce X2 as output, where there's no known test that can distinguish X1 from X2. Consider three such processes:
P1 - A digital upload of X1 is created.
P2 - X1 is cryogenically suspended and subsequently restored.
P3 - X1 lives for a decade of normal life.
Call F(P) the probability that X2 is in any sense that matters not the same person as X1, or perhaps not a person at all.
Do you think F(P1) is more than epsilon different from F(P2)? Than F(P3)?
Do you think F(P2) is more than epsilon different from F(P3)?
For my part, I consider all three within epsilon of one another, given the premises.
Do you think F(P1) is more than epsilon different from F(P2)? Than F(P3)? Do you think F(P2) is more than epsilon different from F(P3)?
Erm, yes, to all three. The two transitions all involve things which are initially plausible and have not been driven down to epsilon (which is a very small quantity) by subsequent research.
For example, we still don't have great evidence that brain activity isn't dynamicly dependent on electrical activity (among others!) which is destroyed by death/cryonics. All we have are a few scatter-shot examples about hypothermia a...
A new paper has gone up in the November 2011 JET: "Ray Kurzweil and Uploading: Just Say No!" (videos) by Nick Agar (Wikipedia); abstract:
The argument is a variant of Pascal's wager he calls Searle's wager. As far as I can tell, the paper contains mostly ideas he has already written on in his book; from Michael Hauskeller's review of Agar's Humanity's End: Why We Should Reject Radical Enhancement
John Danaher (User:JohnD) examines the wager, as expressed in the book, further in 2 blog posts:
After laying out what seems to be Agar's argument, Danaher constructs the game-theoretic tree and continues the criticism above:
One point is worth noting: the asymmetry of uploading with cryonics is deliberate. There is nothing in cryonics which renders it different from Searle's wager with 'destructive uploading', because one can always commit suicide and then be cryopreserved (symmetrical with committing suicide and then being destructively scanned / committing suicide by being destructively scanned). The asymmetry exists as a matter of policy: the cryonics organizations refuse to take suicides.
Overall, I agree with the 2 quoted people; there is a small intrinsic philosophical risk to uploading as well as the obvious practical risk that it won't work, and this means uploading does not strictly dominate life-extension or other actions. But this is not a controversial point and has already in practice been embraced by cryonicists in their analogous way (and we can expect any uploading to be either non-destructive or post-mortem), and to the extent that Agar thinks that this is a large or overwhelming disadvantage for uploading ("It is unlikely to be rational to make an electronic copy of yourself and destroy your original biological brain and body."), he is incorrect.