Hi Enigma,
If immortal has the same relation to mortal as immaterial has to material, it means that the immortal are not mortal, and have no mortality. This is spoken of God: “the blessed and only potentate, the King of the kings and Lord of the lords, who only is having immortality, dwelling in light unapproachable, whom no one of men did see, nor is able to see, to whom is honour and might age-during! Amen.” (1 Timothy 6:15-16)
It is also a hope spoken of the resurrection: “we shall be changed:for it behoveth this corruptible to put on incorruption, and this mortal to put on immortality; and when this corruptible may have put on incorruption, and this mortal may have put on immortality, then shall be brought to pass the word that hath been written, ‘The Death was swallowed up—to victory; where, O Death, thy sting? where, O Hades, thy victory?’” (1 Corinthians 15:55-54)
I wouldn’t see the use of the word in the NT as an attempt to overcome fear in a defensive sense, but rather in an offensive sense, spurning believers on to keeping the faith. But in that sense it is also extremely materialistic, expecting immortality to resemble mortality in an endless way. I get visions of an old man as God and lots of children surrounding him in heaven, playing on the village green
It is a hope of something different after death - but what?
Of course our brain has millions of imput sources of which the most are filtered out and few get put to memory. The accumulation of memory allows people to function without cognitive abilities over a short time without this deficit becoming apparent. But that all has to do with physical existence.
What is incredibly sturdy - even with Alzheimer, is our emotional intelligence, which can be used to guide people with dementia for example. Now, if this emotional intelligence is the soul (another word for soul is psyche and psychotic afflictions are personality disorders) what is the Spirit or Pneuma?
The Spirit is said to be “the breath of God” breathed into man at creation making him more than an animal - awareness some say, intelligence say others. Now intelligence has a dependancy upon memory which we have located in the brain - we will probably never agree to what it is.
What is fairly certain, is the fact that the “human animal” aspires to more and achieves little of it. He is most promising and most dangerous. He is both crown and base of nature. I think this is the Mystery that is seen to be akin to the Mystery of Life in the universe - and possibly they have the same origin.
Shalom
Bob