It boils down to learning a handful of languages enough that you can make some meaningful contributions or a single language deep enough that you can have a meaningful discussion. Neither approach forgoes learning fundamental theory. I equate learning to master C like learning to master a particular instrument like the violin; it requires knowledge of the instrument's construction, the physics of how it produces sound, and a host of other details that must be mastered before one can really make it sing.
I can study music theory for years and it won't help me play the violin well. It will make composition easier and assist me as I adapt myself to the instrument. However one still has to master the instrument and I see the two being complementary and distinct skills.
The metaphor holds together when you start thinking about the breadth of languages available. For example, my primary instrument is guitar. I've been playing for years and have a good grasp of it. However I recently took up the violin so that I could learn to fiddle and play some bluegrass and Irish folk tunes. I still can't play a single tune well on the violin but my knowledge of string instruments and music theory is certainly making my adoption faster than someone who is starting from the very beginning.
However one must be careful with breadth. I could try to learn to play the mandolin after I've "finished," with the violin. And perhaps a banjo after that. However mastery requires a deep, intimate knowledge: you have to spend time with an instrument, learn its quirks, and practice with it every day. Even the best guitar players practice every day. You don't have enough time in this world to master every stringed instrument.
Harder still is the transition to a completely different class of instrument. Mastering drums and guitar is not impossible but rather difficult as knowledge of one doesn't offer much in learning about the other. Learning C is one thing but learning Common Lisp is learning an entirely different model of computation. Having a grasp of the fundamental theories will help some here but nothing you know about C compilers will help you to understand CL (and vice versa). So be even more suspicious of the depth of a programmer's knowledge if they list more than a few languages on their resume if those languages span entire classes of computational models.
And I don't think there's enough time in this world for even a very competent programmer to say they are a master of more than one or two languages.
Update Added a paragraph on computational models and expanded the instrument metaphor.
I can study music theory for years and it won't help me play the violin well. It will make composition easier and assist me as I adapt myself to the instrument. However one still has to master the instrument and I see the two being complementary and distinct skills.
The metaphor holds together when you start thinking about the breadth of languages available. For example, my primary instrument is guitar. I've been playing for years and have a good grasp of it. However I recently took up the violin so that I could learn to fiddle and play some bluegrass and Irish folk tunes. I still can't play a single tune well on the violin but my knowledge of string instruments and music theory is certainly making my adoption faster than someone who is starting from the very beginning.
However one must be careful with breadth. I could try to learn to play the mandolin after I've "finished," with the violin. And perhaps a banjo after that. However mastery requires a deep, intimate knowledge: you have to spend time with an instrument, learn its quirks, and practice with it every day. Even the best guitar players practice every day. You don't have enough time in this world to master every stringed instrument.
Harder still is the transition to a completely different class of instrument. Mastering drums and guitar is not impossible but rather difficult as knowledge of one doesn't offer much in learning about the other. Learning C is one thing but learning Common Lisp is learning an entirely different model of computation. Having a grasp of the fundamental theories will help some here but nothing you know about C compilers will help you to understand CL (and vice versa). So be even more suspicious of the depth of a programmer's knowledge if they list more than a few languages on their resume if those languages span entire classes of computational models.
And I don't think there's enough time in this world for even a very competent programmer to say they are a master of more than one or two languages.
Update Added a paragraph on computational models and expanded the instrument metaphor.