- Upton Sinclair
- Lodowick Muggleton
- John Campbell Shairp
- Milivoy S. Stanoyevich
- Sigmund Freud
- Sir Edward Abbott Parry
- Lord Alexander Fraser Tytler Woodhouselee
- Charles Frederick Ward
- Walter K. Kelly
- D. H. Lawrence
- Friedrich Wilhelm Nietzsche
- Havelock Ellis
- C. T. Russell
- Francis Newton Thorpe
- Benedetto Croce
- F. C. Holliday
- Thomas O Hagan
- Margaret West Kinney
- E. W. Bullinger
- George Santayana