Just point them in the direction of the GBs words in the Sept. 2007 Kingdom Ministry. Then ask them if they are prepared to discuss/debate doctrines with you, thereby risking serious disciplinary measures by going against the "direction" of the FDS!
*** km 9/07 p. 3 Question Box ***
Does “the faithful and discreet slave” endorse independent groups of Witnesses who meet together to engage in Scriptural research.......or debate?—Matt. 24:45, 47.
No, it does not. And yet, in various parts of the world, a few associates of our organization have formed groups to do independent research on Bible-related subjects. Some have pursued an independent group study of Biblical Hebrew and Greek so as to analyze the accuracy of the New World Translation. Others explore scientific subjects related to the Bible. They have created Web sites and chat rooms for the purpose of exchanging and debating their views. They have also held conferences and produced publications to present their findings and to supplement what is provided at our Christian meetings and through our literature.
Throughout the earth, Jehovah’s people are receiving ample spiritual instruction and encouragement at congregation meetings, assemblies, and conventions, as well as through the publications of Jehovah’s organization. Under the guidance of his holy spirit and on the basis of his Word of truth, Jehovah provides what is needed so that all of God’s people may be “fitly united in the same mind and in the same line of thought” and remain “stabilized in the faith.” (1 Cor. 1:10; Col. 2:6, 7) Surely we are grateful for Jehovah’s spiritual provisions in these last days. Thus, “the faithful and discreet slave” does not endorse any literature, meetings, or Web sites that are not produced or organized under its oversight.—Matt. 24:45-47.
It is commendable for individuals to want to use their thinking ability in support of the good news. However, no personal pursuit should detract from what Jesus Christ is accomplishing through his congregation on earth today. In the first century, the apostle Paul warned about getting involved in exhausting, time-consuming subjects, such as “genealogies, which end up in nothing, but which furnish questions for research rather than a dispensing of anything by God in connection with faith.” (1 Tim. 1:3-7) All Christians should strive to “shun foolish questionings and genealogies and strife and fights over the Law, for they are unprofitable and futile.”—Titus 3:9.
For those who wish to do extra Bible study and research, we recommend that they explore Insight on the Scriptures, “All Scripture Is Inspired of God and Beneficial,” and our other publications, such as those that discuss the prophecies found in the Bible books of Daniel, Isaiah, and Revelation. These provide abundant material for Bible study and meditation, whereby we can be “filled with the accurate knowledge of [God’s] will in all wisdom and spiritual comprehension, in order to walk worthily of Jehovah to the end of fully pleasing him as [we] go on bearing fruit in every good work and increasing in the accurate knowledge of God.”—Col. 1:9, 10.