Are there Non-Regenerate Believers?

The reformed when debating a Lutheran view of apostasy argue that the “falling away” passages refer to those who only had the appearance of being regenerate. They were never true Christians in the first place. Examine the characteristics of these false Christians. 

They can:

be enlightened (Hebrews 6:4)
taste the heavenly gift (Hebrews 6:4)
share the Holy Spirit (Hebrews 6:4)
taste the goodness of God’s word (Hebrews 6:5)
receive eschatological blessings (Hebrews 6:5)
repent (Hebrews 6:6)
understand the truth (James 5:9)
receive grace (Galatians 5:4)
be in fellowship with Christ (Galatians 5:4)
receive the gospel (Matthew 13:20)
have joy in the truth (Matthew 13:20)
have been bought by the Lord (2 Peter 2:1)
escape the evils of the world (2 Peter 2:20)
know Jesus Christ (2 Peter 2:20)

Compare this with what is said in scripture about unbelievers:

they have darkened hearts (Romans 1:21)
their thinking is futile (Romans 1:21)
they have no understanding (Romans 3:11)
they do not seek God (Romans 3:11)
they do no good (Romans 3:12)
they are hostile to God (Romans 8:7)
they cannot submit to God’s law (Romans 8:7)
they cannot please God (Romans 8:8)
their minds are defiled (Titus 1:16)
they are slaves to sin (Romans 6:6)
they hate the light (John 3:20)
they are alienated from Christ (Colossians 1:21)
they cannot understand the gospel (I Corinthians 2:14)
they are blinded from seeing Christ (2 Corinthians 4:3-4)
they cannot receive the Spirit (John 14:16)
they are unable to come to Christ (John 6:44)

Is it possible that these descriptions can all apply to the same group of people? Can these blessings of the first list be applied to those in the second? This would mean that men can receive the word with joy but be unable to understand the word, share in the Spirit but not be able to receive the Spirit, have no understanding and blinded minds but understand the truth, taste the goodness of God’s word yet be unable to understand His word, be alienated from Christ yet be in fellowship with him, be enlightened but have no understanding, be in slavery to sin yet repent and escape the evils of the world, receive grace but not salvation, and know Christ but are unable to come to Him. 

The conclusion is unavoidable; these verses cannot be referring to the same group of people. Those who fall away have truly been saved and have been severed from Christ.