Home  Return to Post

The Danger of Pure A Priori Thought Processes: Philosophy Without Experience

By Damien Manier

“Be a philosopher; but, amidst all your philosophy, be still a man.” - David Hume

(Note: Please reference the list of words at the end of the essay so that we can have a mutual understanding of how I am using them.)

The necessity of both experience and a priori thought to form a solid and consistent philosophy has been a fundamental principle for me since I discovered their meanings. However, I have recently encountered arguments that, as I understand them, posit the possibility of forming philosophical ideas without or contrary to experience or empirical evidence. The problem with this is that it is most unlikely to be possible to form concepts wholly outside of any type of experience. (Due to the very nature of such ideas it is impossible to prove or disprove this statement definitively.) Another objection to pure a priori thought processes being entered into philosophical discourse is that they are not able to be analyzed on fair ground since they are shrouded in ideas unprovable, pro or con. Thus, to rely completely on a priori thought and ignore experience and empirical evidence could be used to hide or deflect the weakness of an argument. I hope to show that the best way to approach a problem is to use experience and empirical evidence as a base and expound upon them with a priori thought processes to form new hypotheses tempered by common sense.
One of the arguments for pure a priori thought process that I have experienced is that by relying on experience and evidence to form my concepts, I have become limited in my formulations. My answer is that I am limited. The limited nature of man's ability to reason, the fallibility of man's senses and his ability to observe and experience the world around him, and the infinite volume of knowledge that man simply lacks should be acknowledged and should be put forward as the reason to doubt our ability to discern the nature of the universe or or form a philosophy of ethics completely within our own fallible minds with no input from experience or empirical evidence.

Using pure a priori thought process also leads to what I call the “Skeptic's dilemma”, where a priori thought process allows us to contemplate infinite possibilities but all are equal without experience to add probability to any of the choices and so no decision, besides an arbitrary one, can be made. For example, if we drop a rock we can imagine many possibilities of what will happen next: the rock falls the ground; the rock levitates; the rock falls upwards or side to side; the rock ceases to exist or disappears; we can even contemplate the possibility that the rock could do some inexplicable or unimaginable action wholly outside of our experience. However, using only a priori thought processes this is far as we can proceed. Without experience no option seems more likely than others and thus the pure a priorist thinker is stuck in the “skeptics dilemma”of being unable to make a decision since all reality is in question and all choices are arbitrary without experience to weigh in favor of imagined possibilities. In this example, experience would lead us to believe that it is probable that the rock will fall to the ground. We can also trace all the imagined possibilities to inspirations based on experience besides the last statement where the concept of inexplicable actions that are wholly outside of our experience is just an acknowledgment of our incomplete knowledge.

The arbitrary nature of the pure a priori thought process will also lead to compounding fallacies as thoughts are put together. Since the pure a priorist has infinite imagined possibilities to choose from to include those not known and they do not limit their choice in any way with experience or empirical evidence the probability of them making the right choice (the choice action that results in the desired effect) is highly unlikely. This idea which could very well not lead to their desired results will then be the only basis for building further ideas since they are supposedly only using internal thought and not experience or evidence. Hence, a single mistake in logic, which is highly likely in the limited human mind, will lead to a chain of logical fallacies since there is no outside criterion, such as experience or common sense, to notice large deviations from what will actually occur from the a prior system of ideas.

Another strong objection to the pure a priori thought process is that since it does not rely or even respect experience or empirical evidence there is no way to challenge it. When confronting people of faith to question their systems of belief, they will likely entertain your challenge and defend their beliefs based on reason, appealing to experience and evidence, up to a point but when they are faced with a challenge for which they have no corresponding evidence or experience they will appeal to faith or belief without evidence in some idea that they have chosen arbitrarily or more likely based on the authority of another person. In proposing an idea based on a pure a priori thought process what defense can the pure a priorist offer to challenges to their idea other than faith or their own authority. In fact, they are likely to attack the challenger's reliance on experience and evidence in order to hide the fact that they have no other standards to rely on besides faith and/or authority. The true danger of this is that if the pure a priorist does actually gain believers to their philosophy they will have to rely wholly on their faith in the authority of the pure a priorist since they are the only source of the idea and the believers will have the potential to be easily manipulated since they can not challenge the authority of the proposed philosophy without renouncing their initial faith and replacing it with experience and empirical evidence to the contrary or at least questioning, with an honest curiosity, the lack of evidence or supporting experience.

Fortunately, most philosophers positing pure a priori ideas that lack evidence or do not resonate with the personal experiences of their audiences are largely ignored and the pure a priori ideas that are contrary to experience are met with a cold reception or even hostility when communicated. Since man, by nature, judges what he experiences in proportional and relative connection to earlier experience it will only be natural for most people to dismiss the ideas of philosophers who try to contradict common sense or the reason built upon their personal experience. How else could they discern between the many philosophies offered to them unless they accepted through authority alone. However, historical examples of people accepting a priori concepts contrary to experience do exist. Some religious leaders have successfully used a priori concepts that have no grounds in empirical evidence to influence their followers to act contrary to their experiences. The pharisees used the concept of God resting on the Sabbath and his commandment that men do the same in a way that prevent farmers from saving their livestock from calamity on the Sabbath, even though their experience based in reason probably led them to the conclusion they should act.

The potential danger of ideas based on pure a priori thought processes and the faith necessary to sustain and propagate them due to their lack of foundation in or even contrary nature in regards to experience or evidence should be apparent. However, it should also be apparent in the dangers of relying solely on experience without a priori thoughts; as this would lead to men acting purely on instinct (acting on prior experience without reflection on that experience). I also understand that fallibility of man affects experience and empirical evidence just as it affects the internal reflections of a priori thought. On an individual level a perception of the world around us based on our senses is not wholly accurate, some would argue it is far from accurate. However, without submitting to the authority of another equally fallible person we have no other way to gather information on the world we live in and make decisions. We must simply recognize our limitations and act accordingly. Equally important, empirical evidence not directly researched and observed by ourselves will require us to process some information based on the credibility of another fallible person without any certainty in our judgments. However, by our nature certainty is an impossible goal and so we should strive and only hope to form judgments of probability.

We should use our full set of tools to flesh out ideas: that of human reason which relies on the idea that “arguments concerning existence are founded on the relation of cause and effect; that our knowledge of that relation is derived entirely from experience; and that all our experimental conclusions proceed upon the supposition that the future will be conformable to the past” (Hume); an a priori thought process that is “confined within...limits” of “compounding, transposing, augmenting, diminishing,” or abstracting from the “materials afforded by the senses and experience” (Hume); the use of experience, empirical evidence, and common sense to assign probabilities to the possibilities imagined using a priori thought; and a return to a priori thought process to consider other possibilities in order to maintain a healthy level of skepticism and continue growing and expounding in your ideas. Hume concluded that when it comes to a priori thought process and experience it would be in vain to “exalt the one by deprecating the other.”


The following list of terms is so that it is more clear what I specifically mean in this essay. Most of these words have meanings that vary widely depending on topic or common usages.

Pure A Priori thought process- the process of forming ideas by using internal reflections without using experience or empirical evidence to determine the probability of an idea working as stated or thought.

A priori- imagined possibilities not necessarily based on experience but not wholly independent of experience either.

Experience- inputs received by the senses or reflections of those inputs received directly or indirectly.

Direct Experience- inputs received by your own senses and reflections on those inputs.

Indirect Experience- inputs, usually reflections from another person, that were not directly observed with your own senses but were gathered from others and judged according to your own standards of credibility that are also based on past experience.

Common Sense- commonly observed phenomenon or shared experiences that have led to wide acceptance of certain ideas.

(Empirical) evidence- quite similar to experience; refers specifically to reflections of observed phenomenon or experience. Faith- firm belief in something for which there is no proof. (true) Skeptic- in philosophy skeptic usually refers to someone who believes there is no such thing as truth, nor is it possible for man to discern reality and since it is impossible to believe in something without truth or reality they do not believe anything.