No doubt Ray Kurzweil and Jeff Hawkins rank among the top original thinkers and IT innovators. Both see computing mirroring the functions of the human brain. But they don't agree on how fast scientists and engineers will develop technologies that exhibit the most complex cerebral traits of humans: self-awareness, emotion, and even a sense of one's own mortality.

Because of technology's exponential growth, Kurzweil sees emotion-laden, self-aware machines being developed by mid-century. Hawkins' view on technology patterned after the human brain is more limited than Kurzweil's prognostications, saying such artificial beings will take centuries, not decades, to create. The brain is just too complex to replicate that quickly. Emotional robots that run amok, Hawkins says, will remain science fiction for a very long time.

I caught up with Kurzweil via cell phone. In the second of five podcasts from our talk, he says society will face some tough choices in mere decades as it decides how to treat technologies that act like humans.

Hawkins share his thoughts in another podcast about a more benign technology, in which devices will be built using hierarchical temporal memory, the patterns found in the neocortex, the part of the brain that differentiates mammals from other vertebrates.

Both men have impressive credentials to make these predictions. Kurzweil--author of the recently published book--The Singularity Is Near: When Humans Transcend Biology--has been at the forefront of technological innovation, as the principal developer of the first omni-font optical character recognition, the first print-to-speech reading machine for the blind, the first CCD flat-bed scanner, the first text-to-speech synthesizer, the first music synthesizer capable of recreating the grand piano and other orchestral instruments, and the first commercially marketed large-vocabulary speech recognition.

Hawkins, of course, is no technology slacker. Give him much of the credit for making the personal digital assistant a mainstay business tool, as founder of two pioneering PDA makers, Palm and Handspring. Now, he started a new company, Numenta, which is developing technology based on the neocortex. His ideas can be found in his book, On Intelligence.

So, who's right? Listen to their podcasts, and tell us what you think by responding in the comments box below.

All InformationWeek podcasts can be found by clicking on Podcast Directory at InformationWeek.com.