Harry Geels: Piketty’s five fallacies

June 9, 2026

_{This column was originally written in Dutch. This is an English translation.}

By Harry Geels

In his recent report, Thomas Piketty once again sets out an ambitious worldview. Climate change, inequality and economic structure are brought together in a single, overarching project. However, his solutions contain five systematic fallacies.

The new Global Justice Report by Piketty and his colleagues reads like a blueprint for a new global economy: one in which we must recognise that prosperity and the climate cannot be viewed in isolation from one another, and that real progress is only possible if we drastically reduce inequality, curb our consumption and distribute the benefits of globalisation more fairly. A new democratic world order is proposed, as otherwise both the green and social transitions would stall.

The report argues that by the year 2100 it will be technically possible to both limit global warming and raise the standard of living for the vast majority of the world’s population, but only if we do four things simultaneously: rapidly becoming more sustainable, wasting less, working less, and implementing a substantial global redistribution, with heavy taxes on top wealth (up to 20% per year for multimillionaires and billionaires). The key message: inequality is the main bottleneck for climate policy and broad prosperity.

Piketty’s aim for a cleaner climate and less inequality is noble. However, the same cannot be said of his plan. In fact, he makes five logical fallacies.

1) The financial fallacy: ‘risk-free return’

Piketty takes a simplistic view of wealth accumulation. Wealth growth is not a stable process of interest or returns, but the result of volatility, failures and uncertainty. For most people, income growth is much more gradual. In fact, Piketty ‘forgets’ to apply a risk adjustment when comparing the rate of return on capital (r) and income growth (g). He bases his analysis on averages.

The returns he studies are ex post averages: they reflect success stories, but less so the failures that counterbalance them. This creates the impression of an almost automatically growing wealth base, whereas in reality risk – and therefore risk compensation – is essential. If taxes on returns and wealth are too high, that risk compensation is reduced, making the wealthy less willing to take risks, which limits economic growth and innovation.

2) The economic fallacy: ‘capital is easily accessible to the government’

Piketty advocates high taxes on wealth and capital, often to levels that are historically unprecedented. In doing so, he implicitly assumes a relatively static system. But capital is the most mobile factor of production we know.

High capital taxes lead to behavioural responses: investments shift, innovation may slow down and activities move to more favourable regimes. Not only does capital move geographically, it also shifts towards less taxable or less productive forms. Ultimately, these effects are borne not only by the wealthy, but by the economy as a whole.

3) The ethical fallacy: ‘the outcome takes precedence over legitimacy’

In Piketty’s analysis, the focus shifts from the question of how wealth is created to the question of how it is distributed. In his approach, ownership shifts from a primarily individual right to something that the community can claim. Ownership is implicitly reduced to a quantity that must be redistributed, with less attention paid to the underlying legitimacy: voluntary exchange, self-determination, risk, entrepreneurship and deferred consumption.

In doing so, Piketty positions himself within the egalitarian and socialist tradition of thought. This stands in contrast to the liberal tradition of, for example, Locke, Smith and Hayek, in which property forms the moral starting point and in which stable property rights not only serve justice but also form the basis for trust, investment and economic order. The ‘community’s right to private capital’ may not be a fallacy, but it is certainly a divergent political-philosophical standpoint.

4) The political fallacy: ‘the world as a single system’

Piketty’s proposals presuppose a high degree of international coordination. Global wealth taxes, international funds and sanctions against non-participating countries are only feasible in a world with strong central control. The reality is one of sovereign states with competing interests and without credible enforcement mechanisms. The proposal ignores the classic ‘collective action problem’: countries have incentives to deviate as soon as it is in their own interests.

5) The logical fallacy: ‘climate as necessary redistribution’

Finally, Piketty directly links climate and income policy. Effective climate policy without redistribution would not be possible. In doing so, he implicitly presents redistribution as a necessary condition. According to the rules of logic, this is dubious.

Climate policy can be designed to be regressive, neutral or progressive and, in an analytical sense, is independent of the chosen income distribution. There are various routes to reducing emissions, such as CO₂ taxes, technological innovation and regulation. His reasoning thus takes on the character of a false dilemma: the climate transition that can only take place through redistribution.

The deeper insight: a difference in approach

What ultimately distinguishes Piketty from many classical economists is his line of reasoning. He starts from the desired outcome – a more equal world – and then seeks the structures necessary to achieve that outcome. Inequality thus becomes the organising variable that must solve other problems.

The traditional economic approach works the other way round: it starts with incentives, behaviour and institutions, and accepts that outcomes follow from these. That difference – from outcome to system (Piketty) versus from system to outcome (the classical approach) – is the real dividing line.

In conclusion

Piketty poses sharp and relevant questions about inequality and climate change. Few would disagree with that. But his answers are less convincing than his diagnosis. They rest on assumptions about risk, behaviour, legitimacy and politics that are by no means self-evident. But the real distinction lies deeper: Piketty fixes the outcome and bends the process, whilst others fix the process and leave the outcome open. And it is precisely there, in that reversal, that Piketty’s analysis loses its power.

This article contains a personal opinion by Harry Geels

More columns by Harry Geels