Philo of Larissa

Life and Historical Context

Philo of Larissa (c.160–c.80 BCE) was a Greek philosopher from Larissa in Thessaly and the last generally recognized scholarch (head) of Plato’s Academy. His life falls in the late Hellenistic period, a time marked by intense intellectual rivalry among Stoics, Epicureans, Peripatetics, and different strands of Platonism and skepticism.

Philo studied in Athens under Clitomachus, himself a pupil and successor of Carneades, the leading figure of the so‑called New Academy. Under Clitomachus, Philo absorbed a strongly skeptical tradition which emphasized the suspension of assent. At some point—probably in the early 1st century BCE—Philo became the head of the Academy. Ancient sources describe him as the last scholarch before the institutional continuity of the Academy was disrupted.

Political and military turmoil shaped his career. Around 88 BCE, during the First Mithridatic War, Sulla’s siege and sack of Athens forced many intellectuals to flee. Philo left Athens, eventually settling for a time in Rome, where he taught and associated with members of the Roman elite. His most famous pupil was Marcus Tullius Cicero, who studied with Philo as a young man and later presented Philo’s views on knowledge and skepticism in Latin for a Roman audience.

The details of Philo’s final years and exact place of death are uncertain. Later sources suggest that he may have traveled in the eastern Mediterranean after leaving Rome, but the testimony is fragmentary. No works of Philo survive under his own name; his doctrines are known mainly through Cicero (especially Academica), later doxographical reports, and hostile or critical accounts from figures such as Antiochus of Ascalon and Sextus Empiricus.

Academic Skepticism and Epistemology

Philo’s importance lies largely in his attempt to reformulate Academic skepticism. He stood at a transitional point between the radical skepticism of Carneades and the more dogmatic Platonism of his own pupil and rival, Antiochus of Ascalon.

Earlier Academic skeptics had argued that certainty is unattainable and that the wise person should withhold assent from all impressions. Carneades, however, introduced the notion of “persuasive” or “probable” impressions (pithanai phantasiai) that could guide action without claiming full knowledge. Philo developed this line into a more systematic, fallibilist epistemology.

According to the reconstruction found in Cicero, Philo maintained several key positions:

• Inaccessibility of certainty: Human cognitive faculties are not reliable enough to guarantee absolute, infallible knowledge. For every apparent certainty, there is the possibility of error.
• Graded confidence in impressions: Although certainty is impossible, some impressions are more coherent, consistent, and experientially robust than others. These can be reasonably accepted as credible or highly probable.
• Assent to the plausible: Unlike the strictest skeptics, Philo allowed that the wise person may assent to such well-tested impressions, adopting beliefs as long as they are regarded as fallible and revisable.
• Practical rationality: This moderate skepticism preserves the possibility of rational deliberation, ethics, and political life, since agents can act on the best-supported beliefs available without claiming absolute knowledge.

Ancient critics accused Philo of abandoning skepticism. Antiochus charged him with “veering toward Stoicism” by conceding too much to the Stoic notion of cognitive impressions (kataleptic impressions)—perceptions that, according to the Stoics, guarantee truth. Philo himself, as represented by Cicero, appears to resist this charge, insisting that his account does not introduce infallible criteria but only relative epistemic standards suited to human limitations.

Later, Sextus Empiricus classified Philo’s position as a “mitigated” or “fallibilist” form of skepticism, distinct from both radical Pyrrhonism and dogmatic schools. Modern scholars often describe Philo’s view as an early, systematically articulated form of fallibilism: the idea that one can hold justified beliefs while acknowledging their possible error.

Relationship to Plato and the Academy

As head of the Academy, Philo stood within the Platonic tradition, yet at a time when that tradition had become deeply intertwined with skepticism. Ancient sources distinguish between the Old Academy (close to Plato himself), the Middle Academy (often associated with a more interpretive and ethical Platonism), and the New Academy, marked by the skeptical turn begun by Arcesilaus and developed by Carneades.

Philo played a pivotal role in debates over whether the Academy should continue in a skeptical direction or return to a more dogmatic Platonism. While he upheld the skeptical method of inquiry—testing arguments on both sides, avoiding claims to certainty—he also sought to reconnect the Academy with certain Platonic doctrines, especially about the general structure of reality and the value of philosophy as a guide to life.

This effort provoked strong opposition from Antiochus of Ascalon, a former student. Antiochus claimed that Philo’s modifications blurred the distinctive skeptical stance of the New Academy and that a return to “Old Academy” Platonism was needed. Antiochus eventually founded a rival, more dogmatic school, often described in modern literature as “Middle Platonism” or a precursor to it.

Thus, Philo’s tenure marks both the culmination and transformation of Academic skepticism. After him, the institutional continuity of the Academy breaks off, and the Platonic tradition re-emerges in more doctrinal, less skeptical forms.

Legacy and Reception

Philo of Larissa’s direct writings are lost, so his legacy survives primarily through the work of others, above all Cicero. In dialogues such as Academica and De natura deorum, Cicero presents Philo as a major authority on skepticism and often aligns his own position with Philo’s moderate, fallibilist stance. Through Cicero, Philo’s ideas entered the Latin philosophical vocabulary and shaped the way educated Romans understood Greek skepticism and Platonism.

Later Pyrrhonist writers, including Sextus Empiricus, treat Philo as a key representative of the Academic tradition, though they criticize his acceptance of probable assent as a step away from full suspension of judgment. For them, his view illustrates one of several possible compromises between dogmatism and radical skepticism.

In modern scholarship, Philo has attracted interest as:

• An important figure in the transition from Hellenistic to later Platonism.
• A source for the fallibilist conception of knowledge, which resembles certain strands of modern epistemology.
• A crucial interlocutor for understanding Cicero’s philosophy, since many of Cicero’s arguments depend on Academic skeptical frameworks derived from Philo.

Because his doctrines are known only indirectly, interpretation remains contested. Some scholars read Philo as fundamentally skeptical, emphasizing the denial of certainty and focus on probability; others see him as moving toward a qualified dogmatism, permitting stable, though fallible, commitments to certain philosophical theses. This ambiguity continues to make Philo of Larissa a subject of debate in the study of Hellenistic epistemology and the history of skepticism.