Through the history of technology, humans have moved from physical interfaces to virtual —graphical user— interfaces. The former being a sometimes a true interface to the machine and sometimes a control panel to the bigger instrument being interacted with. Computer screens display an array of virtual interfaces to interact with the abstract computer brain. Many times this virtual interface is a metaphor for the real world (aka the now infamous skeuomorphism).
Because of the changes in the nature of our interfaces our actions are also mutating: from Press to Click to Tap. Similar, yet each leaner that the previous. If the simplest of actions is the tought, what does it say about the interface?
The most intuitive interface is the no-interface interface.
Do we still need a graphical user interface? Will interfaces become leaner and eventually dissapear? Yes. We can already speak to ask and command (eg. Apple’s Siri). Soon we will send commands with our thoughts; and those commands will be complete concepts that require no intermediary or interface to be understood by our computer. Do you want to turn the lights on? No need for a switch (physical or digital), you only need to get your idea across to the machine. Clap your hands, say your command out loud or just think it. The machine will pick it up and act accordingly. The interface is the communication channel and it is becoming more and more unobtrusive.
The computer of the future is a personal assistant and she has no apparent UI.