Jeffrey Sachs' fourth lecture focuses on how the world can assist the poorest countries – and especially sub-Saharan Africa – to lift populations out of poverty through the application of science and technology.

He begins with a familiar – and credible – message: In an interconnected world, the sustained welfare of the rich depends on the growing welfare of the poor. This is not just a matter of ethics and politics, but also because poverty is a breeding ground for global disease epidemics, environmental challenges and terrorism.

Sachs then dismisses the easy conflation of poverty and corruption. Although corruption is a problem in Africa and elsewhere, it is dwarfed in importance by four critical developmental deficits – low levels of agricultural productivity; killer diseases (for example, malaria and AIDS); poor infrastructure; and high rates of population growth.

There are available technological solutions for each of these deficits, and new emerging technologies will make it easier to solve meet these even more effectively, and at lower cost. But they require finance from the outside world – sub-Saharan Africa is too poor to apply these technologies without significant external assistance. Significant, that is, for Africa, but paltry in Western terms, when compared with, say, the cost of the war in Iraq, the bonuses earned by City financiers and especially in comparison to the wealth of the rich economies.

Some Northern economies do make a credible effort to meet these development challenges. But Sachs key message here is that "countries that take care of their own poor also tend to help the world's poor". More specifically, the Scandinavian economies, characterised by high levels of trust and social and economic solidarity, set the standards for the world's richer nations to emulate.

There is not much to disagree with here, and Sachs' plea for an effective response is laudable and, as he says, an argument which is in the long-term interests of the rich countries. The problem is thus not so much with what is in this Reith lecture, but what is excluded.

We are offered a world which "fixes" Africa's problems from the outside, reminiscent of an earlier development debate in the 1970s and 1980s on "dependency". This is a world which abstracts from internal social and political processes – what are the trajectories of technological development and investment within sub-Saharan Africa? What determines their pace and form? What is the interaction between these internal constituencies and external forces?

There is a glaring absence of social process in Sach's approach. We know from UK experience and the experience of innovation worldwide, that often technological fixes – "more technology", "better technology" – either do not work, or have perverse and unintended consequences.

So, here are some questions to consider. Who are the major actors in this story, both in the North and in sub-Saharan Africa and other poor countries? Does it make sense to talk about "Sweden", "Mozambique" or "Malawi" as if they were functioning wholes with homogenous interest groups? What forms of delivery will ensure that the technologies which Sachs calls for are introduced and managed effectively? Whose technologies are we talking about, what intellectual property rights are involved and what will be the distribution of gains as these technologies are acquired and disseminated in poor countries?

Share your views in the Reith Lectures forum.