Annette Baier (1929 - 2012) was one of the most influential philosophers on trust in the last 100 years. Her work on the nature and ethics of trust has influenced just about every philosopher working on trust today, including me. But nobody is perfect. I was recently re-reading her essay "Trust and Anti-Trust" when I noticed a claim regarding the relationship between love and trust that I'm pretty sure is not quite right, or at least needs some significant qualification. Here's the claim:
The best reason for confidence in another’s good care of what one cares about is that it is a common good, and the best reason for thinking that one’s own good is also a common good is being loved. This may not, usually will not, ensure agreement on what best should be done to take care of that good, but it rules out suspicion of ill will.
There is something right about this, at least if we don't admit the sort of "love" that makes an abuser feel entitled to harm his beloved. To use the Greek terms, this seems true of phileo and agape love: if one has this kind of love for another, then one will see the other's good as in one's own interest--it is a common good (in this her view is much like Russell Hardin's "encapsulated interest" account of trust). In the context, she is concerned with the kind of relationship of trust and trustworthiness that exists between a child and a parent, and is wondering what reason a child old enough to be capable of such reflection could have for believing his or her parents to be trustworthy. Her answer is simply recognition of the parents' love.
Here's why I think a caveat is in order: love might not be such a reliable guide to trustworthiness when it comes to epistemic trust. Epistemic trust is trust with respect to forming beliefs and making knowledge claims. If I have epistemic trust in you, then when you tell me that something is the case, I will believe it, I will take myself to know it, and I will present myself as knowing it (e.g., I might confidently assert it to others as true, rather than hedging by saying, "Well, I don't know, but so-and-so told me that..."). Epistemic trustworthiness (indeed, all kinds of trustworthiness) have both a competence component and a motivational component. A trustworthy person will be both capable of doing that for which she or he is trusted, and will be properly motivated to do it. Obviously love doesn't entail competence. Parents who genuinely love their children will nevertheless be epistemically untrustworthy in those domains about which themselves are ignorantly ignorant (i.e., domains in which they think they know something when they don't). So, at best, love will operate on the "proper motivation" side of the trustworthiness requirements.
Here is why Baier's claim needs qualification when it comes to epistemic trust: if what she says applies just as well to epistemic trust as, say, trust to provide food and shelter, then she would be implying that love is the best eliminator of the error possibility that one’s testimonial source is lying. But is it? Can love motivate one to lie just as easily as tell the truth? Depends on what we mean by “just as easily.” I think that in most situations it would motivate one to tell the truth, but every now and then one might be motivated by love to lie, if one thought that the loved one would be better off shielded from the truth.
Baier said that love eliminates the possibility of ill will on the part of one's trustee, and that seems right. But there are other ways one can fail to have the proper motivation for trustworthiness than by having ill will in the matter. This is why I think that "proper motivation" to tell the truth, rather than "good will", is a condition on epistemic trustworthiness. Sometimes good will can motivate deceitfulness--if not a motivation to lie, at least a motivation to hide the truth in whole or in part. So one friend might tell another that his new haircut looks good, even if it doesn't, if that friend thinks that his believing this would be best for him. One spouse may tell another that her meal, that she spent hours slaving over, tastes good, even though it doesn't. Of course, one could argue that people should always be completely honest with each other about absolutely everything, but I don't think that's an obvious truth. Sometimes our knowledge and, indeed, love of a person could lead us to judge that what would best serve that person's long-term good in a particular case is at least no telling him or her the whole truth, if not outright lying.
In any case, I have no doubt that many people believe this, and live it out. So while love may be a great reason for believing someone to be trustworthy in caring for one's own good, it is not as great a reason for believing that someone is epistemically trustworthy.
Really, though, this is a pretty minor criticism of Baier's view. She has a lot of really good things to say about trust, and I highly recommend her work on the subject.