People use different terms for various metaphysical services, and it can be a bit confusing and vague. The following are my definitions, the way that I use these terms. You may read other explanations that differ from mine. As always, go with what feels right to you, what makes sense for you.
Of course, the first thing is to define “metaphysics.” For me, it is that which is outside the mundane, beyond the physical realm, more than the 3rd dimensional, 5 physical senses experience, outside the confines of time and space. I googled the meaning of metaphysics, and got the following:
“the branch of philosophy that deals with the first principles of things, including abstract concepts such as being, knowing, substance, cause, identity, time, and space.
“mid 16th century: representing medieval Latin metaphysica (neuter plural), based on Greek ta meta ta phusika ‘the things after the Physics,’ referring to the sequence of Aristotle’s works: the title came to denote the branch of study treated in the books, later interpreted as meaning ‘the science of things transcending what is physical or natural.’ “
Now to the various metaphysical services:
An Intuitive senses things about people or events. An Intuitive may know who is calling before answering the phone. Or may just “know” if someone has a problem or is lying. Information is often vague, not fully developed or specific. Receiving information is usually spontaneous and uncontrolled. Intuitives can develop this awareness into finer tuned Psychic sensibilities. (Really, everyone can develop this ability.)
A Psychic “knows” things more specifically or clearly (“clair”) than an Intuitive. We have more practiced control over when Information comes, and it comes through our metaphysical or super senses. Clairaudient = hearing, Clairvoyent = seeing, Clairsentient = knowing, Clairalience = smelling. Probably some other “clairs” I’m missing, but you get the idea.
A Medium can contact the discarnate, those who have walked on from this earthly incarnation and passed into spirit. The Medium is a bridge between the Living and the Dead, helping you talk with and get comfort from someone who has passed on.
A Channel is a “hollow bone,” or conduit for another consciousness, another Being. A Trance Channel’s own personality disappears and a totally different Being speaks through the Channel. There may be changes in the Channel’s voice or even appearance. A Conscious Channel is also being used by another Being, although usually without obvious changes in the Channel’s behavior or physiognomy. The information flowing through either type of Channel is coming directly from another entity … the Channel’s Guides, your Guides, Higher Wisdom Beings, even ExtraTerrestrials.