All in the mind?

Authors inhabiting the minds and thinking processess of people long dead, or not so long dead, or even alive, is a new argument I have stumbled across this week. Beevor and Byatt seem to be against it, and this astonishes me. I think of all the historical novels I have read over the years and think how much poorer my personal book world would have been if all those famous authors of the past had not given us those kingly/queenly thoughts. There are many authors writing today who are very good at creating thought processes for historical characters. I was about to say that so far nothing of mine has included anything but fictional characters - and then I remembered Kings Malcolm and Duncan in Banners of Alba. It is hardly an excuse to claim that so little is known of them that one has to invent, but it is true. I remember Dunnett's King Hereafter and the relationship between Thorfinn/MacBeth and his wife Groa and realise how much of the author's imagination went into that, but I cannot be other than glad she did. The result was a joy to read. I sit here and wonder if at any point Dunnett gave us their actual thoughts, and realise I would have to go and check to be sure, but I feel that she did not. A good author's craft can convey many things without inhabiting thought processes. Is that allowable, I wonder? I must go back and re-read Byatt and Beevor!