He makes some good points, but I think he exaggerates his evidence. In particular, while the Drake equation and TTAPS equation both have unknown terms, at least some of the TTAPS equation terms can be estimated through observation and experimentation -- a far cry from "none of the variables can be determined. None at all." Insisting that a line of inquiry be abandoned simply because it is difficult to measure exact values seems contrary to the investigative spirit of science. Of course, Crichton is correct that we should not be drawing firm conclusions from fuzzy numbers.<p>Likewise, just because many scientists share a consensus about something doesn't mean they are necessarily wrong; scientists share a consensus on the ineffectiveness of Laetrile, the relative harmlessness of aspartame, and the unlikelihood of cell phones causing cancer. These things are hard to prove absolutely, and may even be incorrect in specific circumstances, but in absence of better evidence, a consensus is the best we can have.<p>I found this juxtaposition funny:<p><i>There is no shortage of other examples. In the 1920s in America, tens of thousands of people, mostly poor, were dying of a disease called pellagra. [...evidence of pellagra as dietary problem...] They continued to deny it until the 1920s.</i><p>Also this one:<p><i>When he said it wasn't enough, he put the critics' essays on his web page and answered them in detail. Scientific American threatened copyright infringement and made him take the pages down. [...] Speeches contained on this site are the property of Michael Crichton and may not be reproduced, copied, edited, published, transmitted or uploaded in any way without express permission.</i>