What is the unpardonable sin against the Holy spirit?

Mt. 12:32 has been sources of controversy and even mental agony for so many people. 'Sin against the son of man will be forgiven, but sin against the Holy Spirit will no be forgiven.' Is the first 'son of man' any son of man or Jesus Christ? Whether it is any man or Christ, that part of the verse is not a big problem, because those who sinned against Christ were forgiven and Christ Himself prayed for their forgiveness. Sin against the Holy Spirit is not the so called mortal sin contrasted against the venial sin in the Roman Catholic theology on the basis of 1 Jn. 5: 16. Neither is it any sin about which one feels true repentance. Sin against the Holy Spirit is the blindness of the eye of the spirit in such a way that the stage of cataract operation is over. When one looks at Jesus Christ and calls His brilliance darkness, his spiritual eye must be utterly blind. When Jesus is called Beelzebub, it is sin against the Holy Spirit. There is no pardon for it in this world or in the world to come because such a person does not have any guilty conscience against anything and does not feel the need of repentance ever. Any penitential heart, which truly repents of one's sin is sure to get the pardon of Christ. The sinner who commits the sin against the Holy Spirit is already committed to Satan as he or she has sunk to the level of satan (Rom. 1: 24, 26,28). Any one who feels truly sorry for the sins committed and wants to forsake it and live a new life of purity has not committed any sin against the Holy Spirit and should not feel that one has no forgiveness.