The Wall Street Journal tells us this morning that Apple chief Steve Jobs had a liver transplant and is expected back at work this month as scheduled.

What's fascinating though is the way Apple shares have been performing in his absence, up 78% since reaching a two year low in January after news broke of him taking leave of absence. As the Atlantic Monthly says it means investors are coming to terms with the idea of their favorite CEO's mortality which raises a very important question: does it really matter to Apple whether Jobs returns? How much difference can a CEO make, anyway?

David Pearl from Epoch Investment Partners says the performance of Apple shares tell us one thing: the company has shown it can perform very well without Jobs and that it might be getting ready for his departure. "If you look at the performance of Apple over the last year from a fundamental point of view, it's been terrific. They've proven the company can run without him being there day to day. No one lives forever, and you have to build the company with the talent to succeed the founders ... He's a creative genius, without question. At the same time, the company is building itself for the day Steve isn't there, whether it's next year or in 10 years," he told Bloomberg.

Still, short term share performance aside, it's hard to imagine Apple with Jobs' innovative drive and flair. Let's watch this space.