One of the most difficult issues in patent law is obviousness because of its inherently fuzzy tests, factors, and boundaries. Much like the reasonable person standard in torts, there are many ways to address obviousness. One issue that arises frequently is the classic problem of hindsight. Examiners examine an application with inherent hindsight - they see the invention and then go look for it. When they cannot find it, they must evaluate whether it would be obvious based on the state of the art - a question that is difficult to answer without being influenced by hindsight. In this way, the job of the examiner is not just difficult, but unnatural. That is why rules have been set out which must be rigorously followed in order to avoid the "attraction of the siren hindsight" and not "fall victim to the insidious effect of a hindsight syndrome wherein that which only the inventor taught is used against its teacher." See our previous post on hindsight.

One way in which the issue arises in patent prosecution is when an applicant points out that the examiner has combined references using the applicant's own teaching, rather than based on the references themselves. Often an examiner responds to this argument with the following boilerplate response (i've seen it a hundred times if i've seen it once):

So how do you respond to this? Well, one option is to make sure that the law is clearly summarized, rather than relying on the USPTO's boilerplate. Hindsight reasoning is improper unless there is a reason to combine the elements as claimed; and the problem to be solved is gleaned from the prior art, not from the applicant's specification. Often examiners will argue that simply because something "can" be done, then that is enough of a reason to do it. But that is a red herring. Of course it "can" be done - that is why the inventor is claiming it as an invention. If it couldn't be done, the invention would be worthless (and have an enablement problem).

Examiners also are prone to define the problem in terms of its solution, which the Federal Circuit has confirmed is illustrative of hindsight in selection of the prior art.  Insite Vision Inc. v. Sandoz, Inc., 783 F.3d 853, 859 (Fed. Cir. 2015).

Make sure to hold the Office to the case law which requires that the teaching, suggestion, or motivation must come from the references or the knowledge of one skilled in the art, without the benefit of knowledge of the application. When the references themselves are lacking, reliance on the knowledge of one skilled in the art should be supported by evidence, not merely examiner argument (under the APA). 

A recent example illustrating this approach is found in the PTAB decision for SN 15/187,124 related to a ski boot sock that enables ease in donning and doffing ski boots. The examiner argued the motivation to make a combination was to solve an issue the cited reference already addressed, thus confirming hindsight:

So, when you feel that there is a hindsight problem, and the examiner simply parrots back the above boilerplate, delve into the facts and details so that you can articulate why the Office has failed to meet its burdens in properly establishing obviousness, thereby leaving the only reasonable conclusion as being that the rejection is based on impermissible hindsight. Proving a negative is hard, and not the applicant's burden, so don't take it on as your primary approach.