The "Spirits In Prison"

1 Peter 3:19 briefly states that Jesus, after being made alive, made proclamations to imprisoned spirits whom verse 20 calls beings who disobeyed in the days of Noah, perhaps making these spirits the "sons of God" or their offspring from Genesis 6 that sexually engaged with humans before the great flood.  There is another group of beings that is very likely the same one Peter speaks of.  In either case, if this passage is at all consistent with the blatant, repeated teaching of the Old Testament on the true state of death before resurrection, it is in no way talking about Jesus seeing souls in Sheol before he resurrected.  The text says he was made alive before his proclamation, and dead humans are currently unconscious or totally nonexistent on the level of the mind (Ecclesiastes 9:5-10). 

The only spirits the Bible specifically says are imprisoned would be a subcategory of fallen angels mentioned in 2 Peter 2:4 and likely in Jude 1:6, beings confined with chains in the dungeons of what Peter calls Tartarus until their eschatological judgment.  This lone reference to Tartarus (Jude does not mentioned the name of where its fallen angels are kept) does not clarify what sins these angels committed in order to be bound and set aside until they are moved to the lake of fire (Matthew 25:41).  It does indicate that the demons are not being tormented, just imprisoned.  Even for the demons for whom hell was created, as Jesus says in the aforementioned verse from Matthew 25, torment during the wait for their final judgment and punishment is not justice.

Peter is the New Testament author who says both that Jesus spoke with spirits in prison before he returned to the Jesus in resurrection and that there are certain demons chained in Tartarus until "the great day."  This alone would suggest that these two verses address the same group of spirits, which are not human at all, though 1 Peter could be mentioning a different set of fallen angels.  If 1 Peter 3:19 did teach a conscious intermediate state for the human dead before their resurrection, it would more importantly contradict the Old Testament teaching of unconsciousness for the dead in Sheol (Ecclesiastes 9:5-10 again, as well as Job 3:11-19 and Psalm 88:10-12), which is only disturbed by means such as sorcery (the witch of Endor summoning the spirit of Samuel in 1 Samuel 28 would not at all necessitate that the dead are conscious by default right now!).

Any philosophical conflict between the Old Testament and New Testament, in the case of morality, the afterlife, or anything else, would mean that the New Testament contradicts the preceding ideas and books it itself claims are true.  The Old Testament can be true independent of the New Testament's veracity, but the opposite is not true.  Like how the Quran affirms the Torah, the New Testament affirms the Old Testament, and if it, like the Quran does, also contradicted something that it requires to be true, then it would have to be false on at least that point.  Now, the New Testament does not contradict Ecclesiastes, Job, Psalms, or any other part of the Bible that teaches that the dead are unperceiving--if their consciousness exists at all--until they are resurrected to face eternal bliss or the second, final death.

Jesus could have conversed with spirits at some point before or after his resurrection without them being human spirits, and the dead could be unconscious without anything about this being contradicted or vice versa.  Nothing about 1 Peter 3:19 would require that its own truth, if the New Testament is indeed true, logically necessitates that the dead are anything other than nonexistent or sleeping without thought until their bodies are reformed, their souls are reawakened, and they stand before God to experience their eternal life or to be sentenced to the lake of fire and wholly, permanently die (2 Peter 2:6).  Until that time or some other affiliated eschatological event, the demons of 2 Peter 2:4 wait in chains, almost certainly the particular spirits Peter had already referenced before.