From Confident Christianity - Relativism -A Central Heresy of our Culture
And so it can happen that you present the Gospel clearly and faithfully only to be met by the response, 'That is nice for you to believe that. Personally, I'm into Zen Buddhism.'
The Gospel seems to roll like water off a duck's back. Unless you make the right diagnosis, you may be left with the impression that you haven't prayed enough or that they are being morally obtuse, when in fact they have not understood what you are saying.
Of course, no-one is a consistently thought-out relativist. You cannot argue that relativism is true in an absolute sense! At best it can only be relatively true. However, many people easily slip into relative ways of thinking. One minute they are talking as though truth was absolute and its opposite is untrue, the next minute they are talking as though there is nothing that is true outside our perception of it.
Francis Schaeffer wrote about the need to establish antithesis:
'This little formula, 'If you have A it is not non-A', is the first move in classical logic. If you understand the extent to which this no longer holds sway, you will understand our present situation... The shift has been tremendous. Thirty years ago you could have said such things as 'This is true' and you would have been on everyone's wavelength. Everyone would have been talking to each other as though the idea of antithesis was correct. Thus in evangelism you would have begun with the certainty that your audience understood you.' (The God Who is There.) The first task then is to realize what is happening and not proceed until you are sure they are talking in terms of what Schaeffer was driven to call 'true truth'.
Certain aspects of the Gospel help people to see the all-or-nothing truth implications of what we are saying - for instance, the tomb was either empty on that first Easter or it was not. It could not have been both. It could not have been empty for some people but not for others. Similarly, we shall either all appear before the judgment seat of Christ or we shall not, and whether or not that happens will not be decided on whether or not we believe it, but on other grounds entirely!