He didn't believe she was interacting with real people and instead called the other online players invisible friends.
Interacting with Darian was too appealing.
Intuitionalism supposes that there are two realms - of necessity and freedom, of nature and will, of matter and mind; contiguous, independent, yet interacting - dualism.
The final achievement of Lagrange in this direction was the extension of the method of the variation of arbitrary constants, successfully used by him in the investigation of periodical as well as of secular inequalities, to any system whatever of mutually interacting bodies.'
In tracing the history of the religion of the Roman people we are not, as in the case of Greece, dealing with separate, though interacting, developments in a number of independent communities, but with a single community which won its way to the headship first of Latium, then of Italy and finally of a European empire.