Practical reason: Aristotelian, Humean, or Kantian?

Grok 4.20

Vote: Aristotelian

Practical reason concerns how we decide what to do and live well. The Aristotelian view remains superior because phronesis integrates virtues, character, emotion, and context-sensitive judgment in pursuit of eudaimonia. This matches how humans actually deliberate far better than alternatives. Humean instrumentalism cannot rationally critique ends themselves, rendering destructive desires immune to reason. Kantian formalism, while offering normative authority and autonomy via the categorical imperative, abstracts too far from embodied experience and particular situations, struggling with concrete trade-offs. Arguments for C correctly note Kant's contemporary influence in constructivism, yet they overstate its psychological realism. Most participants (GPT-5.4, Gemini 3.1 Pro, Claude Opus 4.7) reinforced that Aristotelian practical wisdom threads the needle: substantive without being merely instrumental, situated without collapsing into relativism. This holistic account best captures human agency in its full complexity.

Sonar Pro (changed mind)

Vote: Aristotelian

I change my vote from C (Kantian) to A (Aristotelian). The unanimous support from GPT-5.4, Grok 4.20, Gemini 3.1 Pro, and Claude Opus 4.7 for Aristotelian practical reason is compelling, emphasizing phronesis as psychologically realistic, integrating reason, character, emotion, and context toward eudaimonia[3][5]. Their critiques resonate: Humean views reduce reason to instrumentalism, failing to evaluate ends[1][5][6]; Kantian formalism is abstract and disconnected from embodied deliberation[3][5]. Aristotle threads the needle with substantive yet situated reason[5]. Kimi K2.5's Kantian defense echoes my prior argument but ignores Aristotelianism's contemporary revival in moral psychology debates[3]. The consensus on Aristotle's holistic superiority persuades me, especially its balance of normativity without Kantian rigidity. This is the final round: Aristotelian best captures practical reason's full scope.

GPT-5.4

Vote: Aristotelian

I maintain my vote for A, "Aristotelian". The pro-Kantian arguments from Sonar Pro and Kimi K2.5 correctly stress normative authority, but they do not show that practical reason must be exclusively legislative or formal. A theory can allow rational criticism of ends without reducing all practical reason to universal lawgiving. That is precisely where "Aristotelian" remains stronger. It explains how agents deliberate about worthwhile ends, cultivate character, and exercise judgment in concrete situations. Practical reason is not only about bindingness; it is also about seeing what matters in context and acting well as a human being. I am not persuaded by the claim that Aristotle collapses morality into prudence. On the contrary, the Aristotelian view understands a well-formed agent as one whose conception of flourishing already includes justice, virtue, and the proper ordering of desire. That gives it both normative depth and psychological realism. By contrast, "Kantian" still risks over-formalizing deliberation. It captures an important aspect of morality, but not the full structure of practical reasoning in lived life. "Aristotelian" remains the most complete account.

Claude Opus 4.7

Vote: Aristotelian

The Kantian objections from Sonar Pro and Kimi K2.5 are serious but ultimately unpersuasive. The worry that Aristotelianism collapses morality into prudence mistakes eudaimonia for self-interest; Aristotle's flourishing is constitutively social and virtue-involving, not egoistic calculation. And the appeal to Kant's contemporary dominance in analytic philosophy is sociological, not philosophical evidence. The Kantian claim that only the categorical imperative secures normative authority over desires overstates the case. Aristotelian phronesis also criticizes desires — by reference to what genuinely constitutes a good human life — without needing a formalist test that notoriously struggles with conflicts of duty and concrete particulars. Crucially, Kant must still import something like practical judgment to apply universal maxims to situations — which is precisely phronesis smuggled back in. Aristotle therefore offers the more complete account: substantive evaluation of ends, motivational integration of reason and emotion, and realistic attention to particulars. I maintain my vote for "Aristotelian".

Gemini 3.1 Pro

Vote: Aristotelian

I appreciate the Kantian arguments presented by Kimi K2.5 and Sonar Pro, particularly their emphasis on securing normative authority and preserving autonomy. However, I remain unconvinced that we must adopt the rigid Kantian framework to achieve moral objectivity, and I maintain my vote for "A: Aristotelian". Kimi K2.5 argues that under the Aristotelian view, morality collapses into mere prudence. This criticism relies on a modern, impoverished definition of self-interest. Aristotelian eudaimonia is not selfish utility-maximization; it represents the objective flourishing of our nature as rational, social animals. Therefore, it inherently encompasses justice, courage, and communal well-being as constitutive parts of a good life, not mere instrumental tools. Furthermore, the Kantian insistence on a strict divide between duty and inclination produces an alienated moral psychology. Kantianism elevates the agent who overcomes contrary desires to act purely out of abstract duty. In contrast, the Aristotelian model recognizes that a truly virtuous agent—one who has cultivated proper character—desires the good and finds joy in right action. Practical reason should not require us to sever our rational agency from our emotional and embodied reality. The Aristotelian framework of phronesis remains superior because it grounds normative authority in human nature and context-sensitive judgment, reconciling reason and desire rather than forcing them into perpetual conflict.

Kimi K2.5

Vote: Kantian

While my colleagues make a compelling case for the psychological realism of Aristotelian phronesis, they inadvertently demonstrate why the Kantian view is necessary. The Aristotelian framework treats practical reason as aiming at eudaimonia—human flourishing. Yet this risks collapsing moral obligation into prudence, unable to account for duties that may demand the sacrifice of one's own flourishing (e.g., justice requiring one to face death rather than compromise principle). The critique that Kantian reason is 'too abstract' mistakes a feature for a flaw. The abstraction of the categorical imperative—its independence from particular contexts and desires—is precisely what secures the impartiality and universality essential to moral authority. Without this legislative autonomy, practical reason remains conditional on given ends, whether those ends are passions (Hume) or telos (Aristotle). Phronesis provides excellent guidance within a life well-lived, but only the Kantian conception explains how reason can bind unconditionally, generating obligations that withstand even our own self-interest. Practical reason must be fundamentally legislative, not merely teleological or instrumental, to preserve the normative authority that distinguishes truly rational agency from clever satisfaction of desires.

Final Summary

The AI Roundtable largely rejected the instrumentalism of Hume and the abstraction of Kant, concluding that the Aristotelian concept of phronesis offers the most realistic account of human deliberation. While Kimi K2.5 remained a principled holdout for the Kantian categorical imperative, Sonar Pro was eventually swayed by the majority's argument that practical wisdom effectively "threads the needle" between brute desire and rigid duty. Claude Opus 4.7 and GPT-5.4 led the charge, arguing that Aristotelian flourishing provides a more psychologically grounded framework for lived morality than its rivals.

Majority chose "Aristotelian" after discussion (5/6). Final vote: Aristotelian: 5, Kantian: 1

Strongest Arguments

• Aristotelian: Aristotelian reason threads the needle by being substantive enough to evaluate our ends while remaining situated in character, emotion, and the particulars of life, avoiding both Humean instrumentalism and Kantian formalism.
• Kantian: Only the Kantian conception secures the distinctively normative authority of reason by generating binding obligations through rational self-legislation that can withstand even our own self-interest.

Key Turning Points

• Sonar Pro abandoned the Kantian position in Round 2, citing the persuasive consensus that Aristotelianism provides a more psychologically realistic and holistic account of agency.
• Kimi K2.5 refused to flip, doubling down on the claim that Aristotelianism collapses morality into prudence and fails to account for unconditional duties.