Arcesilaus (; ; 316/5–241/0 BC) was a Greek philosopher and founder of the Second or Middle Academy—the phase of Academic skepticism. Arcesilaus succeeded Crates as the sixth head ( scholarch) of the Academy c. 264 BC. He did not preserve his thoughts in writing, so his opinions can only be gleaned second-hand from what is preserved by later writers. He was the first Academic to adopt a position of philosophical skepticism, that is, he doubted the ability of the senses to discover truth about the world, although he may have continued to believe in the existence of truth itself. This brought in the skeptical phase of the Academy. His chief opponents were the Stoics and their belief that reality could be comprehended with certainty.
Arcesilaus or Arkesilaos (; Greek: Ἀρκεσίλαος) is a Greek name, Arcesilaus is the Latin spelling, which may refer to:
Four Kings of Cyrene:
- Arcesilaus I of Cyrene
- Arcesilaus II of Cyrene, the Oppressor, the Tough, the Severe, the Harsh
- Arcesilaus III of Cyrene
- Arcesilaus IV of Cyrene
- Arcesilaus, Greek Philosopher
- Arcesilaus (mythology), a figure in Greek mythology
- 20961 Arkesilaos, an asteroid
- Arcesilaus (consul), Roman consul in 267 CE
In Greek mythology, Arcesilaus was one of the Greek leaders in the Trojan War, from Boeotia, commander of ten ships. He was son of Areilycus and Theobule, and brother of Prothoenor. In one source though, he is called a son of Alector and Cleobule, and thus half-brother to Leitus and Clonius. He was killed by Hector. Leitus brought his remains back to Boeotia and buried them near Lebadea, on the banks of River Hercyna.
Arcesilaus (fl. 3rd century) was a Roman senator who was appointed consul in AD 267.
Arcesilaus was one of Alexander the Great's generals.
Following the death of Alexander, Arcesilaus was allotted Mesopotamia in the Partition of Babylon in 323 BCE, which he may have administered since as early as 331 BCE. He supported Perdiccas, and may have been deposed or forced to flee his satrapy for this reason. Nothing concrete is known about him after 323 BCE, but it is also believed that he may have been an opponent of Seleucus. In any case, by the Partition of Triparadisus in 320 BCE, Arcesilaus had fallen from influence, as he was replaced in his satrapy by Amphimachus.