Philipians 4:6-9Paul writes: " Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God.And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus. Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things. Those things, which ye have both learned, and received, and heard, and seen in me, do: and the God of peace shall be with you." I believe that this passage gives us the two "spiritually-associated mental processes" we should have as followers of Christ: prayer and meditation. The reason meditation is good is because it's an internal discipline. We help ourselves, not hurt ourselves, when we calm our mind long enough to dwell on the things listed in this verse. I think the key is to "think on these things" though, not opposing things. I would also recommend it in that context. Other spiritually-associated mental processes, on the other hand (astral projection, divination, etc., etc.) are dangerous and in opposition with God's desire for us.