If each occurrence of “is” here is interpreted as identity (“absolute” or non-relative identity), then this argument is indisputably valid. Things identical to the same thing must also be identical to one another. The relative identity trinitarian argues that one should read the “is” in 1 and 2 as meaning “is the same being as” and the “is” in 3 as meaning “is the same divine Person as”. Doing this, one may say that the argument is invalid, having true premises but a false conclusion.