Artificial intelligence (AI) in their highly cited book by that name has been described by Stuart J. Russell and Peter Norvig as intelligent agent design consisting of the following:
The unifying theme of the book is the concept of an intelligent agent.
In this view, the problem of AI is to describe and build agents that
receive precepts from the environment and perform actions. Each such
agent is implemented by a function that maps percepts to actions, and
we cover different ways to represent these functions, such as
production systems, reactive agents, logical planners, neural
networks, and decision-theoretic systems. We explain the role of
learning as extending the reach of the designer into unknown
environments, and show how it constrains agent design, favoring
explicit knowledge representation and reasoning. We treat robotics and
vision not as independently defined problems, but as occurring in the
service of goal achievement. We stress the importance of the task
environment characteristics in determining the appropriate agent
In contrast to AI the term machine intelligence appears in a more sub-specialized or mechanical computational context, for example a natural language translation machine, a Turning machine, and more generally Raymond
Kurzweil's (1990) Age of Intelligent Machines treats AI in the context of computer science and intellectual history in general.
I suppose one could claim that not every artifice is silicon based, that some could be constructed from biological neurons grown in a Petri dish, in which case we could construct an artificial intelligence that is not especially a machine intelligence. In other words, not every artifice is a machine.