What is true goal of deep learning?

When I first read the question, I was just as baffled. You should have tagged AI and I would have understood what you meant. Now onto your question: although my experience in AI theory is limited, the best way to summarize deep learning conceptually is this: While human-like deductive reasoning, inference, and decision-making by a computer is still a long time away, there have been remarkable gains in the application of AI techniques and associated algorithms. A familiar instance of an AI solution includes IBM's Watson, which was made famous by beating the two greatest Jeopardy champions in history, and is now being used as a question answering computing system for commercial applications. In addition to speech recognition and natural language (processing, generation, and understanding) applications, AI is also used for other recognition tasks (pattern, text, audio, image, video, facial, …), autonomous vehicles, medical diagnoses, gaming, search engines, spam filtering, crime fighting, marketing, robotics, remote sensing, computer vision, transportation, music recognition, classification, and so on.