Need of artificial intelligence:

Artificial Intelligence may be seen as just the latest tool in the philosopher's toolbox for answering these all questions about the behavior of human intelligence, following in the footsteps of  logic,  biology, mathematics, cognitive  science psychology  and  all others.  Some questions that philosophy has wrangled with are: "We know that we are more 'intelligent' than the other creature but what does this really mean?" and "How many of the activities that we call intelligent may be replicated by computation (for example algorithmically)?"

For an example, the ELIZA program described below is a typical example from the sixties where a very simple program raised some serious kind of questions about the behavior of human intelligence. Amongst other things, ELIZA helped psychologists and philosophers to question the idea of what it means to 'understand' in natural language (for example English) conversations

By saying that Artificial Intelligence helps us understand the nature of human intelligence in society, we should notice that AI researchers are increasingly studying multi-agent systems, roughly speaking, which are, collections of AI programs able to cooperate/compete and communicate on small job towards the completion of big tasks.  This means that the social nature of intelligence, rather than, individual, is now a subject within range of computational studies in AI.

Certainly, humans are not the only living, and the questions of life (including intelligent life) poses even bigger questions. Surely, some Artificial Life (ALife) researchers have big plans for their software. They want to use them to:

Give birth to new life forms.

A study of Artificial Life will surely throw light on what this means for a difficult system to be 'alive'. Furthermore, ALife researchers hope that, in creating artificial life-forms, given time, intelligent nature will emerge, mostly like they did in human evolution. Therefore, there can be practical applications of an ALife approach. In particular, evolutionary algorithms (where parameters and programs are evolved to perform a specific task, rather than to exhibit signs of life) are becoming mainstream in AI.