The iPad promises to be a very big deal: not just because it’s the next big over-hyped thing from Apple, but because it fundamentally shifts the way that humans will interact with computing.

Let’s call this the “fourth turning” of the computing paradigm.

Calculators

Early “computers” were electro-mechanical, then electric, and then later all electronic. But the metaphor was constant: you pushed buttons to enter either values or operators, and you had to adhere to a fixed notation to obtain the desired results. This model was a “technology” in the truest sense of the word, replacing “how” a pre-existing task got done. It didn’t fundamentally change the user, it just made a hard task easier.

8-Bit Computers: Keyboards

The early days of computing were characterized by business machines (CP/M, DOS, and character-based paradigms) and by low-end “graphics and sound” computers like the Atari 800, Apple II, and Commodore 64.

The promise here was “productivity” and “fun,” offering someone a more orderly typewriting experience or the opportunity to touch the edges of the future with some games and online services. But the QWERTY keyboard (and its derivatives) date back to at least 1905. And the first typewriters were made by Remington, the arms manufacturer.

The keyboard input model enforces a verbal, semantic view of the world. The command line interface scared the hell out of so many people because they didn’t know what they might “say” to a computer, and they were often convinced they’d “mess it up.” During this era, computing was definitely still not a mainstream activity.

More of the population was older (relative to computing) and had no experience with the concepts.

The Mouse, GUI, and the Web

Since the introduction of the Macintosh, and later Windows, the metaphors of the mouse, GUI, and the web have become so pervasive we don’t even think about them anymore.

But the reality is that the mouse is a 1970’s implementation of a 1950’s idea, stolen by Apple for the Lisa from Xerox PARC. Windows is a copy of the Macintosh.

The graphical computing metaphor, combined with the web, has opened the power of the Internet to untold millions, but it’s not hard to argue that we’re all running around with Rube Goldberg-like contraptions, cobbled together from parts from 1905, 1950, and 1984 respectively. Even so, the mouse alone has probably done more to open up computing than anything else so far.

The mouse enforces certain modes of use. The mouse is an analog proxy for the movement of our hands. Most people are right handed, and the right hand is controlled by the left hemisphere of the brain, which science has long argued is responsible for logic and reason. While a good percentage of the population is left handed, the fact remains that our interactions with mice are dominated by one half of the brain. Imagine how different your driving is when you only use one hand.

While we obviously use two hands to interact with a keyboard, some cannot do that well, and it continues a semantic, verbal mode of interaction.

iPad

The iPad will offer the first significant paradigm shift since the introduction of the mouse. And let me be clear: it doesn’t matter whether hardcore geeks like it now, or think it lacks features, or agree with Apple’s App Store policies.

The iPad will open up new parts of the human brain.

By allowing a tactile experience, by allowing people to interact with the world using two hands, by promoting and enabling ubiquitous network connections, the iPad will extend the range and the reach of computing to places we haven’t yet conceived.

Seriously. The world around us is reflected by our interactions with it. We create based on what we can perceive, and we perceive what we can sense. The fact that you can use two hands with this thing and that it appears to be quick and responsive is a really big deal. It will light up whole new parts of the brain, especially the right hemisphere — potentially making our computing more artistic and visual.

Just as the mouse ushered in 25 years of a new computing paradigm, pushing computing technology out over a much larger portion of the market, the iPad marks the beginning of the next 25 years of computing.

And before you get worried about how people will type their papers and design houses and edit video without traditional “computers,” let me answer: no one knows. We’ll use whatever’s available until something better comes along.

But computing platforms are created and shaped by raw numbers and the iPad has every opportunity to reach people in numbers as-yet unimagined. That will have the effect of making traditional software seem obsolete nearly overnight.

When the Macintosh was released, it was widely derided as a “toy” by the “business computing” crowd. We see how well that turned out.

This time, expect a bright line shift: BIP and AIP (before iPad and after iPad). It’s the first time that an entirely new design has been brought to market, answering the question, “Knowing everything you know now, what would you design as the ultimate computer for people to use with the global network?”

It’s 2010, and we don’t need to be tied down to paradigms from 1950 or 1905. Everything is different now, and it’s time our tools evolved to match the potential of our brains and bodies.