Patricia Greenspan

Department of Philosophy
University of Maryland



Popular and scientific discussions of the implications of genetics for responsibility often bring up the threat of determinism in connection with the philosophical problem of free will.

However, these worries turn out to have little bearing on the standard free will issue in modern philosophy, or free will versus determinism. See my NEGATIVE ARGUMENT for details.

The real threat to freedom, insofar as it suggests determinism, seems to be widespread explanation of behavior in terms of inherited reactive traits that interfere with behavioral control.

This issue of control harks back to the notion of voluntary action derived from Aristotle and applied to modern psychology. I sum this up as free will versus psychological constraint. See POSITIVE ARGUMENT.

The threat of genetic causation to freedom on this account turns on a form of emotional motivation. However, there are other possibilities of emotional influence that may or may not undermine free will. See IMPLICATIONS.


Free will versus determinism, or the standard problem of free will in modern philosophy, isn't really at issue in the worries about genetic causation of behavior.

The reason, stated simply, is that "determinism" implies universal causation, causation of all (behavioral and other) events. The threat of determinism as posed by modern science therefore applies no more to genetic causation than to any form of scientific explanation of behavior in terms of prior causes, whether genetic or environmental.

Most philosophers hold that causation is really no threat to free will (a view called "compatibilism," or "soft determinism"). But even if it were, the threat wouldn't depend particularly on genetic explanation.

Instead, the results of genetics that seem to threaten free will don't apply directly to specific behavioral events--acts-- but rather to general traits of temperament: act tendencies, typically based on emotional reactive tendencies.

For example, some trait on the order of "aggressive impulsivity" is currently suggested as a genetic factor in violent criminal behavior. But this wouldn't mean that genes cause a particular agent to commit a violent crime but at most that genes give rise to emotional reactive tendencies in certain circumstances that make such behavior likely.


Free will versus psychological constraint seems to be the real question at issue in many popular discussions of genetic determinism.

This version of the free will question is concerned only with certain causes of behavior, those that involve some sort of internal constraint on action and hence interfere with the agent's behavioral control.

It can be traced back to Aristotle's first condition on voluntary action, which rules out force or compulsion. But Aristotle thought of compulsion as involving an "external" source of behavior. This leaves it unclear what to say about cases of control by forces within the agent's own emotional makeup.

For instance, in a case of extreme shyness--a reactive trait with genetic sources--an agent's control might seem to be thwarted by his own temperament. That is, shyness as a personality trait subjects the agent to emotional responses that can limit his feasible behavioral options.

In such cases emotions can interfere with behavioral control by making alternative forms of behavior difficult for the agent--not just (and perhaps not quite) impossible, as on a deterministic account.

Thus, someone who's very shy might be unable to raise a coherent question in discussion because his heart beats wildly when he tries. And something similar might be said about the inability to restrain oneself that's at issue in "aggressive impulsivity."

The results of explaining all behavior in this way would indeed resemble determinism--and would undermine the picture of moral character and education that philosophers derive from Aristotle.


Emotions are often thought of as interfering with freedom of action. They may do so, according to the account suggested for shyness, in cases where they increase the difficulty of some of the agent's alternatives.

What's at issue here isn't causation of behavior by emotion but rather interference with rational decision-making.

There are other cases, however, and my argument questions the contrast commonly taken for granted between emotions as causal determinants of behavior and normal reasons for action.

Where emotions undermine freedom on the account suggested, they essentially threaten the agent with a bad state of affairs (emotional discomfort). They may be causes of behavior too, but that issue seems to be irrelevant to questions about behavioral control.

Do emotions undermine freedom in other ways? Aristotle's notion of the voluntary also rules out ignorance; and in some cases the effects of emotion on thought and attention may interfere with rational decision-making.

Even if the agent is able to do otherwise, that is, emotional upset may cloud his perception of the reasons for action, or the alternatives to a particular action.

In recent papers I explore an independent model of emotional unfreedom based on physiological deficit of the means of self-control, as in current explanations of impulsivity in terms of serotonin shortage.2


1 This is a revised version of a poster presented at the eighth conference of the International Society for Research on Emotions in 1994.

2 See, e.g., "Genes, Electrotransmitters, and Free Will," in D. Wasserman and R. Wachbroit (eds.), Genetics and Criminal Behavior: Methods, Meanings, and Morals (New York: Cambridge University Press, forthcoming).

Last revised, 5/15/98, by P. S. Greenspan