What ensures a straightforward and fruitful debate is a resolute search for truth, not allowing one's own desires or the public's to take control. A sensible person, Muslim or non-Muslim, is expected to seek truth and to avoid error sincerely.
Most of the well-known Muslim scholars were very careful in this regard. Al-Imam al-Shafi`i, for instance, used to say: "I never talked with someone but sincerely wished that Allah keep him, protect him from sin and misdeed and guide him; and I never debated with someone but sincerely wished that we would come upon truth, regardless of whether he or I should be the one to think of it first."
Abu Hamed al-Ghazali says also in this connection: "Cooperation in seeking truth is inherent to religion, but sincerity in the pursuit of truth can be distinguished by certain conditions and signs. A diligent seeker of truth may be compared to one who is looking for his lost camel. It would be immaterial for him if he or another person should be the one to find it. Likewise, a sincere truth-seeker would perceive his partner as a helper rather than an adversary, and would be grateful to him if he should guide him to truth."
In another place of Volume 1 of Al-Ihya al-Ghazali says: "Over-enthusiasm is a mark of corrupted scholars, even when the case they are defending is true. By showing excessive enthusiasm for truth and their contempt of their opponents, the latter would be stimulated to retaliate and react in the same manner. They would be driven to stand for falsehood and to be true to the label attributed to them.
If the champions of truth had spoken kindly to them avoiding publicity and humiliation they would have succeeded in winning them over. But as it is, a person who enjoys a place of prestige is strongly inclined to preserve his position by attracting followers, and the only way to that is to boast and to attack or curse adversaries."
To conclude, a debate must be conducted fairly and calmly, without showing any excitement or roughness, and without compromising the chances of arriving at the truth. Debaters should avoid spiteful argumentation and word play, as such behaviour poisons the atmosphere, arouses hostile attitudes and may well end in deadlock.