David Pogue asks how we can know if privacy switches on the iPhone actually do anything in “In Tech We Don't Trust” [TechnoFiles]. We could know this if the software were not closed source but open to inspection. By far the biggest advantage of open source software is that people all over the world can review it to see that it does what it says it does—and only that.

River Att
Manchester, England

In “Simulating a Living Cell,” Markus W. Covert describes the remarkable achievement of the first complete computer model of an entire single-celled organism, the bacterium Mycoplasma genitalium. Would it be feasible now to sequentially disable as many as possible of the bacterium's 525 genes while still allowing the model cell to divide, as a means of investigating how an even simpler organism might have existed in the past and point the way to a possible route back to the origin of life?

Gordon Lee
via e-mail

COVERT REPLIES: I and others are in fact considering how to go about deleting genes to find viable strains that have fewer genes than M. genitalium. It's an interesting problem for a few reasons: First, there are many potential solutions. Second, the order matters—every gene that you knock out has consequences; in some cases, one gene has to be taken out before another one can be, or else the cell dies. We are hoping that we can use our models to generate insight into the best approach and possibly come up with a design for a cell based on that insight.

One of our toughest problems is simply that each simulation (a cell dividing one time) takes about 10 hours, so generating the number of simulations that we would need is computationally daunting. With luck, we will have an answer in a few years.

Vaclav Smil's otherwise excellent article on the factors that make a transition to renewable energy slow and gradual, and on the policies that might hasten it [“The Long Slow Rise of Solar and Wind”], does not mention the huge global subsidies enjoyed by fossil fuels (some half a trillion dollars annually). This makes it difficult for renewable energy to compete. Understanding of the urgency of switching to renewable energy sources and improving efficiency is greatly impeded by this distortion of the economy.

Peter Elliston
Clontarf, Australia

Among the evidence that we will be slow to move to renewables, Smil cites the 50 to 60 years it took to transition from wood to coal and from coal to oil. I am reminded of a caveat that comes with strategic-planning statements from investment advisers when quoting fund performance: past performance is no guarantee of future performance.

Those periods of transition took place in circumstances significantly different from the transition to natural gas, beginning in 1930. And the circumstances since then are drastically different. One difference is the explosive growth in population in the 20th century. Another is the growth in demand/expectation of domestic consumerism. But the main difference is the knowledge of the consequences of human activity vis-à-vis carbon fuels. This knowledge would indicate that if humanity indulged in the luxury of letting the unregulated capitalist market proceed at its own rate, we might well be doomed to an unlivable planet before we complete the coming transition.

There are enormous obstacles to undertaking a transition plan. Those who hold legal title to carbon-based, climate-changing fuels are unwilling to relinquish the profits from their reserves even if the well-being of the biosphere requires that they do so. And humans have a tendency to think that what they observe in their lifetime is normal and can be reasonably expected to continue even when it is clearly a historical anomaly.

Richard Fahlman
Texada Island, B.C.

The scientific evidence cited in arguments against Copernican heliocentric cosmology in the 16th and 17th centuries, as described in “The Case against Copernicus,” by Dennis Danielson and Christopher M. Graney, ought not lead us to ignore the enormous—and tragic—social consequences of religious opposition to this revolutionary idea. Christianity long ago allied itself with a geocentric cosmology, with Man at the apex of a special Creation, possessed of an immortal soul and capable by perfect free will of choosing good or evil.

The Copernican, Darwinian and Freudian revolutions have laid waste this comforting ideology. The rejection of evolution, of climate change, of even the possibility of benefits from genetically modified organisms reflects a self-destructive distrust of science that stems largely from bruised religious sensibilities. This wound to modern society will not yield to scientific education alone.

Jeff Freeman
Rahway, N.J.

While it was insightful, “Our Unconscious Mind,” John A. Bargh's article on how unconscious processes affect our decision making, left me a little unsatisfied. He ends one paragraph by stating that “to make our way in the world, we need to learn to come to terms with our unconscious self,” but he neglects to offer suggestions. I believe meditation has helped me a lot.

Joe Christie
via e-mail

Bargh describes a study asking participants to judge fitness for public office based on fleeting glimpses of photographs of the candidates. I was disappointed that many interesting follow-up questions were not pursued. For instance: Is there a predictable IQ level above which a person would merely laugh when asked to participate in such an idiotic task? Is the level of the participants characteristic of the voting population as a whole?

Steve Munden
via e-mail

In the 50, 100 & 150 Years Ago column, compiled by Daniel C. Schlenoff, the item called “Battling Trachoma,” excerpted from a January 1964 article, refers to nearly 500 million people then being infected with that disease.

Your readers might like to know that since that time, the number of people infected has dropped to 21.4 million. Whereas some of the reduction is from general improvement in hygiene and living conditions, much of it is the result of a global initiative to eliminate blinding trachoma sponsored by the World Health Organization, which builds on the SAFE strategy: surgery for trichiasis (inward-turning eyelashes), antibiotics, facial cleanliness and environmental improvement.

Hugh Taylor
Melbourne School of Population and Global Health, Australia