Pluralism versus Periodization.

In his ingenious bid to restore grand narratives, Frans van Lunteren misleadingly implies that there is a single story to tell about the past. In its favor, his nontrumphalist and metaphorical scheme encourages contextualization and emphasizes objects rather than theories or individuals. Unfortunately, he has selected an arbitrary starting point, and his four emblematic machines—the clock, the balance, the steam engine, the computer—do not bear equivalent relationships to the particular period they are held to represent. This is important because metaphors readily solidify into reality, so that this model risks being interpreted as a progressive sequence of increasing precision and complexity that leaves little room for the biological sciences. Van Lunteren’s initiative might be extended by changing the time structure or by focusing on concepts rather than specific artifacts.