In The Structure of Science (subtitled The Problems in the Logic of Scientific Explanation), the philosopher Ernest Nagel outlined four kinds of explanations that are common in scientific works. They are the following, each briefly explained [1, 2]:
Deductive explanations: in these, the thing being explained (explicandum) is a valid logical conclusion of an argument that must have more than one premise. Having established good reasons for them to be true, these premises should: have some initial conditions; a general law; and, entail the conclusion, but not be entailed by it.
Probabilistic explanations: in these, the premises for explanation do not lead to a logical conclusion of the explicandum, but they make it probable.
Functional or teleological explanations: whereby the explicandum is explained in terms of its function in a larger system or in causing something.
Genetic explanations: in this case, a sequence of real events constitute the premises for an explanation. It is impossible to explain a thing without following its complete history of occurrences.
[1] Ayer, A. J., and Ernest Nagel. Scientific American 204, no. 6 (1961): 197-203. Accessed April 13, 2021. http://www.jstor.org/stable/24937499.
[2] Hendriks-Jansen, H. (1996). In Praise of Interactive Emergence or why Explanations Don’t Have to Wait for Implementations. In Boden, Margaret A. (ed.) (1996). The Philosophy of Artificial Life. Oxford University Press.