Origen indeed speaks of the Celsus to whom he is replying as an Epicurean, and here and there Epicurean opinions are expressed in the fragments of the original work that Origen has preserved.

But Origen himself was somewhat puzzled to find that the main principles of the author were rather Platonic or Neo-platonic than Epicurean, and this observation has been confirmed by modern enquiry.

The Celsus of Origen is in reality a Platonist.
It still being acknowledged that the friend of Lucian was an Epicurean, this discovery seemed fatal to the supposition that he was the author of the work against the Christians.

Accordingly there was a tendency among critics, though not quite a unanimous tendency, to separate again the two personalities which had been united.

At this point Dr.Keim comes upon the scene, and he asks the question, Was Lucian's friend really an Epicurean?
Lucian nowhere says so in plain words, but it was taken as a _prima facie_ inference from some of the language used by him.