Aristotle

==== Scientific style ====
[[File:Two of Aristotle's Growth Laws.svg| thumb | left | upright=1.4 | Aristotle inferred growth laws from his observations on animals, including that [[brood size]] decreases with body mass, whereas [[gestation]] period increases. He was correct in these predictions, at least for mammals: data are shown for mouse and elephant.]]

Aristotle did not do experiments in the modern sense.{{sfn| Taylor | 1922 | page=42}} He used the ancient Greek term ''pepeiramenoi'' to mean observations, or at most investigative procedures like dissection.{{sfn| Leroi | 2015 | pages=361–365}} In ''Generation of Animals'', he finds a fertilized hen's egg of a suitable stage and opens it to see the embryo's heart beating inside.{{sfn| Leroi | 2011}}{{sfn| Leroi | 2015 | pages=197–200}}

Instead, he practiced a different style of science: systematically gathering data, discovering patterns common to whole groups of animals, and inferring possible causal explanations from these.{{sfn| Leroi | 2015 | pages=365–368}}{{sfn| Taylor | 1922 | page=49}} This style is common in modern biology when large amounts of data become available in a new field, such as [[genomics]]. It does not result in the same certainty as experimental science, but it sets out testable hypotheses and constructs a narrative explanation of what is observed. In this sense, [[Aristotle's biology]] is scientific.{{sfn| Leroi | 2015 | pages=365–368}}

From the data he collected and documented, Aristotle inferred quite a number of [[biological rules|rules]] relating the life-history features of the live-bearing tetrapods (terrestrial placental mammals) that he studied. Among these correct predictions are the following. Brood size decreases with (adult) body mass, so that an elephant has fewer young (usually just one) per brood than a mouse. [[Life expectancy|Lifespan]] increases with [[gestation period]], and also with body mass, so that elephants live longer than mice, have a longer period of gestation, and are heavier. As a final example, [[fecundity]] decreases with lifespan, so long-lived kinds like elephants have fewer young in total than short-lived kinds like mice.{{sfn| Leroi | 2015 | page=408}}{{Clear}}