Judges are human, they will use empathy sometimes, need to understand -- at times with some emotional connection -- others to judge various things, they will use empathy. It is in effect a component of judging generally. The attempt by some to limit this to special situations is mythical, even if they might not like the fact judges they frequent leaned one way or the other in their empathy. A totally objective standard might be the ideal, but it's at best a legal fiction. A citation in a recent dissent by Justice Ginsburg is fitting:
[I]t might appear to the lay mind that we are treading on the brink of a precipice of absurdity. Perhaps the admonition of Professor Thomas Reed Powell to his law students is apt; "If you can think of something which is inextricably related to some other thing and not think of the other thing, you have a legal mind."
I also saw reference to the need for empathy in judging mentioned in an article discussing how recognizing the interests of animals is important in formulating an ideal system of justice. Understanding the law requires "empathizing with" the judged, and a failure to do this for some is factored in:
[P]art of the reason John Hart Ely argued for special protections for discrete and insular minorities was not just that they have lesser access to the political process, but also that society tends to lack empathy toward them due to prejudice, or simply due to the lack of accurate knowledge that arises from discreteness and insularity.
It is an interesting article overall by someone who periodically provides essays for Findlaw. But, she is not the one who sometimes references interests of animals, so I was a bit surprised when coming across it. The article has an interesting proposal per taxation:
For example, in the tax code, exemptions for dependents should logically cover everyone in a household who is legitimately dependent on others for his or her sustenance—including non-human companion animals. Such exemptions attempt to recognize the reality that a household with dependents must use some of its income to care for them—and that reality is no less genuine when it comes to non-human companion animals than when it comes to children. Though the two groups have very different needs, both have needs that require money to satisfy. Of course, the current tax code is not a model of analytical consistency and has been profoundly affected by political bargaining. But, again, society should strive for an ideal—and an ideally just tax code would include non-human animals as dependents.
IOW, it would make sense to allow people to use animals as dependents on their taxes. This makes sense for various reasons. We get deductions of varying amounts for various things, so why not something for companion animals, particularly if they are strays and/or taken from shelters or the like? It might be logical to give special preferences to these, even if it is a relatively small amount. Of course, the positive value of animals generally can be a reason to consider too. Finally, possibly, this can be limited to some animals (cats/dogs over goldfish).
The author also favors use of federalism to provide experimentation on the subject. The whole article, though it is somewhat legalistic in tone, is worth reading.