| Abelard, Peter (11) |
| Abrabanel, Judah (2) |
| Abramowski, Edward (1) |
| Abravanel, Isaac (3) |
| Adamson, Robert (2) |
| Adelard of Bath (4) |
| Adler, Mortimer J. (7) |
| Adorno, Theodor W. (10) |
| Aenesidemus (2) |
| Agamben, Giorgio (3) |
| Agrippa, Heinrich Cornelius@ (15) |
| Ajdukiewicz, Kazimierz (2) |
| al-Farabi, Abu Nasr (3) |
| al-Ghazali, Abu Hamid (7) |
| al-Kindi, Yaqub ibn Ishaq (5) |
| al-Razi, Abu Bakr (8) |
| Albertus Magnus@ (14) |
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| Alcott, Amos Bronson (6) |
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| Alexander Polyhistor@ (2) |
| Alighieri, Dante@ (58) |
| Alston, William P. (6) |
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| Ambrose of Milan, St.@ (23) | |
| Ammonius Saccas (4) |
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| Augustine of Hippo, St.@ (129) |
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| Austin, John Langshaw (7) |
| Averroes (11) |
| Avicenna (8) |
| Ayer, Alfred Jules (6) | |
