Are there social regularities? Is there anything like a "law of nature" that governs or describes social phenomena?
My view is that this is a question that needs to be approached very carefully. As a bottom line, I take the view that there are no "social laws" analogous to "laws of nature", even though there are some mid-level regularities that can be discovered across a variety of kinds of social phenomena. But care is needed because of the constant temptation of naturalism -- the idea that the social world should be understood in strong analogy with the natural world. If natural phenomena are governed by laws of nature, then social phenomena should be governed by "laws of society." But the analogy is false.
Of course there are observable regularities among social phenomena. Urban geographers have noticed a similar mathematical relationship in the size distribution of cities in a wide range of countries. Durkheim noticed similar suicide rates among Catholic countries -- rates that differ consistently from those found in Protestant countries. Political economists notice that there is a negative correlation between state spending on social goods and the infant mortality rate. And we could extend the list indefinitely.
But what does this fact demonstrate? Not, I want to argue, that social phenomena are "law-governed". Instead, it results from two related facts. First, there are social-causal mechanisms; and second, there is some recurrence of common causes across social settings.
Take the mechanism of "collective action failures in the presence of public goods." Here the heart of the mechanism is the analytical point that rationally self-interested decision-makers will take account of private goods but not public goods; so they will tend to avoid investments in activities that produce public goods. They will tend to become "free riders" or "easy riders." The social regularity that corresponds to this mechanism is a "soft" generalization -- that situations that involve a strong component of collective opportunities for creating public goods will tend to demonstrate low contribution levels from members of affected groups. So public radio fundraising will receive contributions only from a small minority of listeners; boycotts and strikes will be difficult to maintain over time; fishing resources will tend to be over-fished. And in fact, these regularities can be identified in a range of historical and social settings.
However, the "free rider" mechanism is only one of several that affect collective action. There are other social mechanisms that have the effect of enhancing collective action rather than undermining it. For example, the presence of competent organizations makes a big difference in eliciting voluntary contributions to public goods; the fact that many decision-makers appear to be "conditional altruists" rather than "rationally self-interested maximizers" makes a difference; and the fact that people can be mobilized to exercise sanctions against free riders affects the level of contribution to public goods. (If your neighbors complain bitterly about your smoky fireplace, you may be incentivized to purchase a cleaner-burning wood or coal.) The result is that the free-rider mechanism rarely operates by itself -- so the expected regularities may be diminished or even extinguished.
What I draw from this is pretty simple. It is that social regularities are "phenomenal" rather than "governing": they emerge as the result of the workings of common social-causal mechanisms, and social causation is generally conjunctural and contingent. So the regularities that become manifest are weak and exception-laden -- and they are descriptive of outcomes rather than expressive of underlying "laws of motion" of social circumstances.
And there is a research heuristic that emerges from this discussion as well. This is the importance of searching out the concrete social-causal mechanisms through which social phenomena take shape. We do a poor job of understanding industrial strikes if we simply collect a thousand instances and perform statistical analysis on the features we've measured against the outcome variables. We do a much better job of understanding them if we put together a set of theories about the features of structure and agency through which a strike emerges and through which individuals make decisions about participation. Analysis of the common "agent/structure" factors that are relevant to mobilization will permit us to understand individual instances of mobilization, explain the soft regularities that we discover, and account for the negative instances as well.