Loren speaks of hardware driving the success of the Tablet PC, and Iggy agrees, going so far as to say that “computing with a pen is unnatural.”
“Computing with a pen is unnatural.” Okay, I can agree with the words, but only to the extent that it's tied to “computing with a keyboard is unnatural,” “computing with a mouse is unnatural,” “computing with a 4-function calculator is unnatural.”
The very idea of “natural” computing is off-base; the computers that we have today are quite unlike any natural form: they are neither static objects nor responsive animals. They have internal state, they react, they generally transfer data to us in high-level abstractions (words, images), but they lack even fundamental awareness of their environment, much less the reactive capacity of any work animal (much less human). Someday, certainly, we'll be able to interact with computers in a “natural” way -- computers will watch and listen to us and their environment and intuit our intent for them. Several breakthroughs will be required before that day.
Iggy's sentiment, though, is not “computing today is in its infancy,” but rather “computing with a pen is less intuitive than computing with mouse and keyboard.” With this sentiment I whole-heartedly disagree. I hammered on the preliminary nature of computing today precisely because the view that a keyboard and mouse is “natural” is incredibly myopic. In the late 80s, I bought a mouse, from Microsoft, for use with my spanking new 286 running DOS. You could use it with Microsoft Word and a small set of DOS-based windowing tools. The mouse was \$99 and was no bargain. Word was inferior to WordPerfect and when programs did use windows (the Turbo IDEs, for instance), it was always faster to use the keyboard (and function keys. Does anyone remember function keys? You know, they're still on the keyboards...).
So in 1989 (say), it would have been totally parallel to say “look, you have to pay a premium for a DOS mouse, it's slow for input, there's no software... Computing with a mouse is unnatural.” And, believe me, there were plenty of people who expressed such sentiments, even with the Macintosh sitting there and telling the story:
To be useful, a hardware innovation (mouse) must be coupled with software innovation (bitmapped windows)
And then along came Desqview 386 (software innovation to exploit the hardware innovation of the 386 and the mouse) and Windows 3.0 & 3.1 and here we are 15 years later with a software ecosystem that has co-evolved with the mouse and keyboard. It is true that it is hard to use a non-mouse pointing device with existing software, even with drawing software where the pen is fundamentally easier to control than a mouse.
It's not that the pen is unnatural, it's that the software has evolved with a bias towards mouse and keyboard
It's true that new form factors, longer battery life, better screens, perhaps more ruggedness -- all of those affect the “the change of scale or pace or pattern" that [the Tablet] "introduces into human affairs" and thus are important to the medium. But there must be software specifically created for the Tablet PC's hardware innovations. Just as applications evolved to exploit the mouse and keybard, so too can they evolve to exploit the pen. And such software will feel natural.
Case in point: Arcs of Fire. While a game with a single-screen and a static background is hardly going to take sales from Half Life 2, there has never been a game that “feels” more like the act of throwing, which is a behavior that's hard-wired into our genes to be pleasurable. Arcs of Fire “feels natural” for that type of game, much more “natural” than the old DOS-based games where you typed in muzzle velocity and angle, or mouse-based games requiring a diagonal motion that's hard to do accurately with a mouse.
The success of the Tablet, at this point, is much, much more reliant on software than hardware.